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B1 noun #7,000 most common 11 min read

地下水

chikasui Top 7,000

Practice it Examples Notes & Tips 地下水 in 30 Seconds

Explanation 地下水 in your Level:

At the A1 level, you only need to know that 地下水 (chikasui) means 'water under the ground.' Think of it as three simple words: 地 (ground) + 下 (under) + 水 (water). You might not say this word often, but you might see it on a sign near a park or a well. It is simply water that you cannot see because it is hidden in the earth. You can remember it by thinking of 'underground' (chika) like a subway train, and 'water' (sui). It is the water that stays under the subway! In very simple Japanese, you could say: 'Tsuchi no naka no mizu desu' (It is water inside the soil).

At the A2 level, you can start using 地下水 (chikasui) in basic sentences about nature and daily life. You might learn that some people drink this water from a well (ido). You can say things like 'Chikasui wa tsumetai desu' (Groundwater is cold) or 'Chikasui wa kirei desu' (Groundwater is clean). You should recognize that this word is more formal than just saying 'mizu' (water). If you go to the countryside in Japan, you might see people using groundwater for their gardens. It's a useful word for talking about where water comes from when it doesn't come from a tap.

At the B1 level, you should be able to use 地下水 (chikasui) in discussions about the environment and social issues. This is the level where you learn about 'pollution' (汚染 - osen) and 'resources' (資源 - shigen). You might read news articles about how factories affect groundwater or how farmers need it for their crops. You should also be able to use compound words like '地下水位' (groundwater level) or '地下水の汲み上げ' (pumping of groundwater). At this stage, you understand that 地下水 is a vital part of the ecosystem and a topic of public interest in Japan.

At the B2 level, you can use 地下水 (chikasui) in more complex arguments and technical descriptions. You might discuss the 'recharge' (涵養 - kanyou) of groundwater or the legal regulations surrounding its extraction. You can explain the difference between groundwater and surface water (地表水) and discuss the consequences of over-extraction, such as land subsidence (地盤沈下). Your vocabulary should include terms like 'aquifer' (帯水層) and 'water quality' (水質). You are expected to understand the nuances of how groundwater quality affects industries like sake brewing or precision manufacturing.

At the C1 level, 地下水 (chikasui) is a term you use fluently in professional or academic contexts. You can analyze hydrological data, discuss the 'hydrogeological' (水文地質学的な) characteristics of a region, and debate the ethics of groundwater privatization. You understand the historical significance of groundwater in Japanese urban planning and how it relates to 'Satoyama' culture. You can read complex legal documents or scientific papers that use this term extensively and can explain the subtle differences between 'chikasui', 'fukuryuusui', and 'yousui' in a professional presentation.

At the C2 level, you have a masterly command of the term 地下水 (chikasui) and all its connotations. You can engage in high-level policy discussions regarding national water security and international water rights. You understand the literary and philosophical metaphors associated with 'underground currents' in Japanese literature. Your usage is indistinguishable from a native expert in hydrology or environmental law. You can navigate the most technical aspects of groundwater modeling and isotopic analysis in Japanese, and you can contribute to global discourses on groundwater sustainability using Japanese as your medium.

Practice it Examples Notes & Tips

地下水 in 30 Seconds

地下水 (Chikasui) means groundwater, water found beneath the earth's surface.
It is a B1 level word used in environmental, industrial, and domestic contexts.
In Japan, it is famous for its role in making high-quality sake and tofu.
Key issues related to it include pollution and land subsidence from over-pumping.

The Japanese word 地下水 (ちかすい - chikasui) is a compound noun that literally translates to 'ground-under-water,' or more naturally in English, groundwater. It refers to the water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations. In Japan, a country characterized by its mountainous terrain and abundant rainfall, chikasui is a vital natural resource that has shaped the nation's history, agriculture, and industry for centuries.

Literal Meaning: The kanji 地 (chi) means earth or ground, 下 (ka) means below or under, and 水 (sui) means water. Together, they describe water that exists beneath the surface.
Scientific Context: In environmental science and geology, it refers to the water found in aquifers. It is distinguished from surface water (地表水 - chihyousui).
Daily Life Usage: People use this term when discussing well water (井戸水 - idomizu), spring water sources, or the environmental impact of construction and pollution on local water supplies.

この地域の農業は豊富な地下水に支えられています。 (Agriculture in this region is supported by abundant groundwater.)

Understanding 地下水 is essential for anyone living in rural Japan or working in fields like engineering, agriculture, or environmental protection. Japan's famous sake breweries often highlight the quality of their chikasui as a key ingredient that determines the flavor profile of their beverage. For instance, the soft groundwater of Fushimi in Kyoto is legendary. Furthermore, the term often appears in news reports regarding environmental issues, such as the contamination of groundwater near industrial sites or the sinking of land (subsidence) caused by excessive pumping.

地下水の汚染が深刻な問題になっています。 (Groundwater pollution has become a serious problem.)

In a broader cultural sense, 地下水 represents the hidden resources and foundations of life. Just as groundwater flows unseen beneath our feet, many aspects of Japanese society and tradition are supported by deep, underlying 'currents' of history and culture. When you use this word, you are often engaging in a discussion that touches upon the environment, health, and the sustainability of natural resources. It is a B1 level word because while the kanji are simple, the contexts in which it is used—ranging from ecology to urban planning—require a more nuanced understanding of societal issues.

工事の影響で地下水の流れが変わってしまった。 (The flow of groundwater changed due to the impact of the construction.)

Hydrological Cycle: In the context of the water cycle, 地下水 is the stage where water infiltrates the soil and moves slowly through the ground before eventually reaching rivers or the ocean.

この工場では、冷却水として地下水を利用しています。 (This factory uses groundwater as cooling water.)

Using 地下水 correctly involves understanding its role as a noun that can be modified by adjectives or linked to other nouns using the particle 'の'. It frequently appears with verbs related to flow, extraction, and protection. Because it is a technical term, it is often found in formal reports, news articles, and academic discussions, but it is also common in everyday conversations about gardening, home building, or local geography.

Common Verb Pairings: 地下水を汲み上げる (kumiageru) - To pump up groundwater; 地下水が流れる (nagareru) - Groundwater flows; 地下水を守る (mamoru) - To protect groundwater.

地震の後、地下水の水位が急激に下がった。 (After the earthquake, the groundwater level dropped sharply.)

When describing the quality of the water, you might use adjectives like 'きれいな' (clean), '冷たい' (cold), or '豊富な' (abundant). In a professional setting, you might discuss '地下水の涵養' (kanyou - groundwater recharge) or '地下水の塩水化' (ensuika - saltwater intrusion). These terms are vital for understanding environmental impact assessments which are common in Japanese news regarding coastal development.

私たちは地下水を汚染から守らなければなりません。 (We must protect groundwater from pollution.)

In rural areas, many households still rely on chikasui for their daily needs. In such cases, the word is used in a very practical sense, often appearing on utility bills or in discussions about water filters. If you are buying land in Japan, you might ask about the '地下水の状況' (groundwater situation) to ensure the land is stable and that water is available if you plan to dig a well.

この井戸は、深い層の地下水を利用しています。 (This well utilizes groundwater from a deep layer.)

For students of Japanese, pay attention to the compound words. '地下水脈' (chikasui-myaku) refers to a groundwater vein or underground stream. '地下水位' (chikasui-i) is the groundwater level. These compounds are very common in technical writing. Using these terms correctly will significantly elevate your Japanese proficiency from a general level to a more specialized or professional one.

Environmental Concerns: 地下水の過剰な汲み上げ (kajou na kumiage) - Excessive pumping of groundwater, which often leads to land subsidence (地盤沈下 - jiban chinka).

飲料水として安全な地下水を確保することが重要です。 (It is important to secure groundwater that is safe as drinking water.)

大雨で地下水が濁ってしまった。 (The groundwater became muddy due to the heavy rain.)

The word 地下水 is ubiquitous in Japanese society, appearing in contexts ranging from the mundane to the highly scientific. You will encounter it most frequently in news broadcasts, especially during segments on the environment, natural disasters, or urban development. For example, after a major earthquake, news anchors will often report on changes in chikasui levels or potential contamination caused by soil liquefaction.

News & Media: Frequent reports on pollution near factories (e.g., the Toyosu market relocation issues) or during droughts when groundwater reserves are low.
Construction Sites: Engineers and workers discuss groundwater management to prevent flooding in basements or tunnels during excavation.

ニュース番組で地下水の放射能汚染について報じている。 (The news program is reporting on radioactive contamination of groundwater.)

In the culinary world, particularly among sake and tofu makers, chikasui is a word spoken with reverence. A master brewer (Toji) might explain that the unique taste of their sake comes from the 'mineral-rich groundwater' filtered through the local mountains. This highlights the word's positive, life-giving connotations, contrasting with the more technical or problematic usage in environmental news.

この豆腐は、美味しい地下水を使って作られています。 (This tofu is made using delicious groundwater.)

Academic settings, such as university lectures in geography, civil engineering, or environmental science, use chikasui as a fundamental term. Students learn about the 'hydrogeological cycle' and the mechanics of how water moves through different layers of the earth. Furthermore, in the legal sector, there are specific laws like the 'Groundwater Law' (though often managed at the municipal level in Japan) that regulate how much water businesses can extract.

学術論文で地下水の流動解析が行われた。 (A flow analysis of groundwater was conducted in the academic paper.)

Finally, you might hear this word in local government announcements. If a city is planning to improve its water resilience, it might discuss using chikasui as an emergency backup for the municipal water system. Residents are often encouraged to know where local wells are located in case of a disaster that cuts off the main water pipes. This practical, survival-oriented context is a key part of the word's presence in the Japanese consciousness.

Real-world Scenario: A real estate agent might say: 'ここは地下水が豊富なので、庭に井戸を掘ることもできますよ' (Since groundwater is abundant here, you can also dig a well in the garden.)

自治体が地下水の質を定期的に検査しています。 (The local government regularly tests the quality of the groundwater.)

この地域の地下水は非常に冷たくて美味しいです。 (The groundwater in this area is very cold and delicious.)

While 地下水 seems straightforward, English speakers often make mistakes by confusing it with other water-related terms or by using it in contexts where a more specific word is required. One of the most common errors is using chikasui when they actually mean 'well water' (井戸水 - idomizu). While all well water is groundwater, not all groundwater is drawn from a well. If you are drinking it at home, you are drinking 'idomizu'. If you are talking about the resource in the earth, you use 'chikasui'.

Mistake 1: Confusing with Tap Water: Some learners use 'chikasui' to mean any water that isn't bottled. Remember that tap water is 'suido' (水道). In many cities, tap water comes from rivers, not groundwater.
Mistake 2: Confusing with Spring Water: Spring water is 'yousui' (湧水). While it originates as groundwater, once it bubbles up naturally, it's called spring water. Using 'chikasui' for a scenic spring might sound a bit too clinical or technical.

❌ 私は毎日地下水を飲みます。(I drink groundwater every day.) -> ⭕ 私は毎日井戸水を飲みます。(I drink well water every day.)

Another mistake involves the kanji. Beginners might confuse 地下 (chika - underground) with 地上 (chijou - above ground). Saying 'chijousui' (地上水) is rare; the correct term for water on the surface is 'chihyousui' (地表水). Additionally, be careful with the pronunciation of 'sui'. It is a long 'u' sound followed by 'i', not 'swee'. Mispronouncing it can make the word unrecognizable to native speakers.

❌ 地下水が蛇口から出ます。(Groundwater comes out of the faucet.) -> ⭕ 水道水が蛇口から出ます。(Tap water comes out of the faucet.)

In a grammatical sense, learners sometimes forget that chikasui is a noun and try to use it as an adjective without 'no'. For example, 'chikasui pollution' must be 'chikasui no osen' (地下水の汚染). Also, avoid overusing the word in casual settings. If you are at a restaurant and want to know if the water is from a local spring, asking about 'chikasui' might sound like you are a scientist conducting an inspection. Using 'mizu' (water) or asking if it's 'tennensui' (natural water) is often more natural.

❌ この川は地下水です。(This river is groundwater.) -> ⭕ この川の源流は地下水です。(The source of this river is groundwater.)

Finally, don't confuse chikasui with 'chikasuidou' (地下水道). The latter means 'sewer' or 'underground drainage system'. Telling someone that your city has excellent 'chikasuidou' (sewers) when you mean 'chikasui' (groundwater) would lead to a very confusing and potentially humorous conversation about the quality of your drinking water!

Vocabulary Distinction: 地下水 (Chikasui): Natural groundwater.
地下水道 (Chikasuidou): Man-made sewers/drainage.

❌ 地下水にゴミを捨てないで。(Don't throw trash in the groundwater.) -> ⭕ 地下水道や川にゴミを捨てないで。(Don't throw trash in the sewers or rivers.)

To truly master the vocabulary surrounding 地下水, you need to understand its relationship with other water-related terms. Japanese has a rich vocabulary for water depending on its source, movement, and purity. Knowing these synonyms and related words will help you choose the most precise term for any situation.

湧水 (ゆうすい - Yousui): Spring water. This is groundwater that naturally flows out to the surface. It is often used in the context of tourism and 'famous water' spots.
井戸水 (いどみず - Idomizu): Well water. This is groundwater that has been accessed via a man-made well. Use this for domestic or agricultural water sources.
伏流水 (ふくりゅうすい - Fukuryuusui): Underflow or sub-surface flow. This is a specific type of groundwater that flows through the gravel layer beneath a riverbed. It is often very pure and used for sake brewing.

この町は地下水よりも湧水で有名です。 (This town is more famous for its spring water than its groundwater.)

In more formal or scientific contexts, you might hear '水資源' (mizushigen - water resources) or '帯水層' (taisuisou - aquifer). If you are talking about the natural environment, '天然水' (tennensui - natural water) is a popular marketing term that often refers to groundwater that has been bottled. Comparing 'chikasui' with 'chihyousui' (surface water like rivers and lakes) is common when discussing the 'total water balance' (水収支 - mizushuushi) of a region.

伏流水は、砂礫層を通ることで自然にろ過されます。 (Underflow is naturally filtered as it passes through gravel layers.)

When discussing pollution, you might hear '浸出水' (shinshutsusui - leachate), which is water that has percolated through waste and may eventually contaminate the chikasui. Understanding these distinctions is crucial for B1 and B2 level learners who wish to participate in discussions about ecology or urban planning. Each word carries a specific 'register'—from the everyday 'idomizu' to the technical 'fukuryuusui'.

この地域では、地下水と地表水を併用しています。 (In this region, they use both groundwater and surface water together.)

In summary, while 地下水 is the most versatile term, choosing the specific alternative based on the context (drinking, science, tourism, or pollution) will make your Japanese sound much more natural and precise. Always consider whether the water is still underground, coming out of the ground, or being used by humans when selecting your vocabulary.

Register and Usage Summary: 地下水: Neutral/General/Scientific.
湧水: Positive/Natural/Scenic.
井戸水: Practical/Domestic/Rural.
伏流水: Technical/High-quality/Brewing.

天然水のラベルには、採取地の地下水の情報が書かれています。 (The labels of natural water contain information about the groundwater at the collection site.)

How Formal Is It?

Fun Fact

In ancient Japan, before the word 'chikasui' was common, people simply used 'ido' (well) or 'shimizu' (pure water) to refer to what we now call groundwater. The term 'chikasui' reflects a more modern, scientific view of the water cycle.

Pronunciation Guide

UK tʃi.ka.su.i

US tʃi.kɑ.su.i

Japanese has pitch accent rather than stress. In 'chikasui', the pitch typically starts low on 'chi', rises on 'ka', and stays high or slightly drops on 'sui' depending on the dialect (Heiban or Atamadaka).

Rhymes With

海水 (kaisui - seawater) 香水 (kousui - perfume) 洪水 (kouzui - flood) 給水 (kyuusui - water supply) 排水 (haisui - drainage) 流水 (ryuusui - flowing water) 噴水 (funsui - fountain) 温水 (onsui - hot water)

Common Errors

Pronouncing 'sui' like 'swee' (English influence).
Merging 'ka' and 'sui' into 'kasui' (skipping a syllable).
Putting the stress on the first syllable like 'CHI-kasui'.
Making the 'u' in 'sui' too long (chika-suuu-i).
Pronouncing 'chi' as 'shi'.

Difficulty Rating

Reading 3/5

Kanji are basic (Grade 2), but the context is often technical.

Writing 3/5

The kanji are easy to write, but the word is long.

Speaking 4/5

Pitch accent on 'sui' can be tricky for learners.

Listening 3/5

Easy to recognize if you know 'chika' and 'mizu/sui'.

What to Learn Next

Prerequisites

地 (chi) 下 (shita/ka) 水 (mizu/sui) 地下 (chika) 水道 (suido)

Learn Next

汚染 (osen) 資源 (shigen) 環境 (kankyou) 井戸 (ido) 地盤 (jiban)

Advanced

涵養 (kanyou) 帯水層 (taisuisou) 伏流水 (fukuryuusui) 水文循環 (suimon-junkan) 透水性 (tousuisei)

Grammar to Know

Noun + の + Noun (Possession/Attribute)

地下水の温度 (The temperature of groundwater)

Te-form for Cause and Effect

雨が降って、地下水が増えた。 (It rained, and [consequently] the groundwater increased.)

Passive Voice for Social Issues

地下水が汚染されている。 (The groundwater is being polluted.)

Potential Form with 'koto ga aru'

地下水が枯れることがある。 (It happens that groundwater dries up.)

Noun + を + Verb (Direct Object)

地下水を守る。 (To protect groundwater.)

Examples by Level

これは地下水です。

This is groundwater.

Simple A is B sentence structure.

地下水は冷たいです。

Groundwater is cold.

Using an i-adjective to describe the noun.

地下水を見ました。

I saw groundwater.

Direct object with the particle 'wo'.

地下水はどこですか。

Where is the groundwater?

Question about location.

地下水があります。

There is groundwater.

Existence verb for inanimate objects.

地下水はきれいです。

Groundwater is clean.

Using a na-adjective.

地下水を飲みます。

I drink groundwater.

Present tense action.

地下水は大切です。

Groundwater is important.

Expressing importance.

この井戸の地下水は美味しいです。

The groundwater from this well is delicious.

Using 'no' to link 'ido' and 'chikasui'.

雨が降って、地下水が増えました。

It rained, and the groundwater increased.

Te-form to show cause and effect.

地下水を使って、野菜を洗います。

I use groundwater to wash vegetables.

Using 'wo tsukatte' to show means.

山にはたくさんの地下水があります。

There is a lot of groundwater in the mountains.

Locational particle 'ni'.

地下水はどこから来ますか。

Where does groundwater come from?

Using 'kara' for origin.

古い町には地下水が多いです。

There is a lot of groundwater in old towns.

Adjective 'ooi' for quantity.

地下水を汚さないでください。

Please do not pollute the groundwater.

Negative request 'naide kudasai'.

地下水の温度は一年中同じです。

The temperature of groundwater is the same all year round.

Compound subject 'chikasui no ondo'.

地下水の汚染が社会問題になっています。

Groundwater pollution is becoming a social problem.

Noun + ga + naru (to become).

この工場は地下水を汲み上げています。

This factory is pumping up groundwater.

Te-iru form for continuous action.

地下水の水位が下がると、地面が沈むことがあります。

When the groundwater level drops, the ground may sink.

Conditional 'to' and 'koto ga aru'.

私たちは地下水を守るための法律を学びました。

We learned about laws for protecting groundwater.

Using 'tame no' for purpose.

この地域では、地下水が農業に欠かせません。

In this region, groundwater is indispensable for agriculture.

Expression 'ni kakasemasen'.

地下水の流れを調査する必要があります。

It is necessary to investigate the flow of groundwater.

Noun + no hitsuyou ga aru.

大雨の影響で、地下水が濁ってしまいました。

Due to the heavy rain, the groundwater has become muddy.

Te-shimau for an unfortunate result.

地下水は貴重な天然資源の一つです。

Groundwater is one of the precious natural resources.

Expression 'no hitotsu desu'.

過剰な地下水の採取は地盤沈下を引き起こす恐れがある。

Excessive extraction of groundwater may cause land subsidence.

Formal expression 'osore ga aru'.

地下水の涵養を促進するために、森を育てることが重要だ。

To promote groundwater recharge, it is important to grow forests.

Using 'sokusin suru tame ni'.

化学物質が地下水層まで浸透してしまった。

Chemical substances have permeated down to the groundwater layer.

Verb 'shintou suru' (to permeate).

この都市は地下水の自噴帯に位置しています。

This city is located in an artesian groundwater zone.

Passive/State 'ni ichi shite imasu'.

地下水の水質基準が厳格化されることになった。

It was decided that groundwater quality standards would be tightened.

Grammar 'koto ni natta' for decisions.

沿岸部では、地下水の塩水化が懸念されています。

In coastal areas, saltwater intrusion of groundwater is a concern.

Passive 'kenen sarete iru'.

地下水の流動解析を行い、汚染の広がりを予測する。

Perform groundwater flow analysis and predict the spread of pollution.

Stem form 'okonai' to link clauses.

地下水は、地表水に比べて水温の変化が少ないのが特徴だ。

A characteristic of groundwater is that its temperature changes less than surface water.

Comparison 'ni kurabete'.

地下水の持続可能な利用に向けた包括的な管理体制が求められている。

A comprehensive management system for the sustainable use of groundwater is required.

Passive 'motomerarete iru' (is required).

帯水層における地下水の滞留時間は、場所によって数千年に及ぶこともある。

The residence time of groundwater in aquifers can reach thousands of years depending on the location.

Verb 'oyobu' (to reach/extend to).

地下水汚染の浄化には、膨大な費用と長い年月を要する。

The purification of groundwater pollution requires enormous costs and many years.

Verb 'yousuru' (to require).

水文循環の観点から、地下水と河川水の相互作用を考察する。

From the perspective of the hydrological cycle, consider the interaction between groundwater and river water.

Expression 'no kanten kara'.

地下水の権利関係をめぐって、自治体間で議論が紛糾した。

Discussions between local governments became complicated regarding groundwater rights.

Expression 'wo megutte' (concerning).

放射性同位体を用いて地下水の年齢を推定する手法が確立された。

A method to estimate the age of groundwater using radioisotopes has been established.

Using 'moite' (using/by means of).

地下水の水位低下は、周辺の生態系に深刻な打撃を与えかねない。

A drop in the groundwater level could potentially deal a serious blow to the surrounding ecosystem.

Auxiliary verb 'kanai' (could possibly).

深層地下水の開発は、新たな水資源確保の切り札として期待されている。

The development of deep groundwater is expected to be a trump card for securing new water resources.

Noun 'kirifuda' (trump card/last resort).

地下水盆の適正な管理は、食料安全保障の観点からも喫緊の課題である。

Proper management of groundwater basins is an urgent issue from the perspective of food security.

Adjective 'kikkin' (urgent/pressing).

地下水の枯渇は、一度発生すれば回復が極めて困難な不可逆的変化を招く。

Once groundwater depletion occurs, it causes irreversible changes that are extremely difficult to recover from.

Adjective 'fukagyakuteki' (irreversible).

法的な枠組みを超えた、広域的な地下水ガバナンスの構築が不可避となっている。

The construction of regional groundwater governance that transcends legal frameworks has become inevitable.

Adjective 'fukahi' (inevitable).

地下水の流動系における不均質性が、汚染物質の挙動を複雑にしている。

Heterogeneity in the groundwater flow system complicates the behavior of pollutants.

Noun 'fukintshusei' (heterogeneity).

気候変動が地下水の涵養メカニズムに及ぼす影響を定量的に評価する。

Quantitatively evaluate the impact of climate change on groundwater recharge mechanisms.

Adverb 'teirouteki ni' (quantitatively).

地下水は「見えない資源」であるがゆえに、その過剰利用が見過ごされがちである。

Because groundwater is an 'invisible resource,' its over-utilization tends to be overlooked.

Grammar 'ga yue ni' (because of/due to).

地下水の保全は、将来世代に対する現役世代の倫理的責務と言えるだろう。

The conservation of groundwater can be said to be the ethical responsibility of the current generation toward future generations.

Noun 'sekimu' (duty/obligation).

地下水排除に伴う圧密沈下のメカニズムを、土質力学の観点から詳述する。

Detail the mechanism of consolidation settlement associated with groundwater removal from the perspective of soil mechanics.

Verb 'shoujutsu suru' (to detail/describe in detail).

Common Collocations

地下水を汲み上げる

地下水が汚染される

地下水の水位

豊富な地下水

地下水の涵養

地下水の水質

地下水脈

地下水の利用

地下水への影響

地下水の枯渇

Common Phrases

地下水が湧き出る

— Groundwater gushes out. Used to describe a spring forming.

地面から地下水が湧き出ている。

地下水に頼る

— To rely on groundwater. Used when a community has no other water source.

この村は地下水に頼って生活している。

地下水を守る会

— Society to protect groundwater. Common name for local environmental groups.

地下水を守る会の活動に参加する。

地下水の流れ

— The flow of groundwater. Used in engineering and geology.

地下水の流れをシミュレーションする。

地下水汚染対策

— Measures against groundwater pollution.

政府が地下水汚染対策を発表した。

地下水の恩恵

— The blessings of groundwater. Expressing gratitude for the resource.

私たちは地下水の恩恵を受けている。

地下水管理計画

— Groundwater management plan. Used by governments.

新しい地下水管理計画を策定する。

地下水の飲用

— Drinking of groundwater.

地下水の飲用には注意が必要です。

地下水の浸透

— Infiltration/permeation of groundwater.

雨水の地下水への浸透を助ける。

地下水の採取制限

— Restrictions on groundwater extraction.

干ばつのため、地下水の採取制限が行われた。

Often Confused With

地下水 vs 地下水道

Means 'sewer' or 'underground drain'. People often add 'dou' by mistake.

地下水 vs 地表水

Means 'surface water'. It's the technical opposite.

地下水 vs 水道水

Means 'tap water'. Not naturally occurring like groundwater.

Idioms & Expressions

"地下水のように流れる"

— To flow like groundwater. Describes something that happens quietly and unseen but steadily.

彼の情熱は地下水のように静かに流れている。

Literary

"地下水脈を探り当てる"

— To find a groundwater vein. Metaphorically, to find the hidden source of a problem or success.

ついにビジネスの成功という地下水脈を探り当てた。

Metaphorical

"地下水が枯れる"

— Groundwater dries up. Can mean a source of inspiration or funds has vanished.

アイディアの地下水が枯れてしまった。

Casual

"地下水のように支える"

— To support like groundwater. To provide essential support from behind the scenes.

彼女の助言が、プロジェクトを地下水のように支えていた。

Polite

"地下水を濁す"

— To muddy the groundwater. To ruin a good situation or a pure reputation.

スキャンダルが町の地下水を濁してしまった。

Metaphorical

"地下水のごとく"

— Just like groundwater. Used to describe something fundamental and pervasive.

伝統は地下水のごとく、人々の生活に浸透している。

Formal

"地下水が溢れる"

— Groundwater overflows. Can represent overflowing emotions or sudden abundance.

喜びが地下水のように溢れ出した。

Literary

"地下水を探す"

— To look for groundwater. Often used for seeking the truth or a hidden cause.

事件の真相という地下水を探し続けている。

Metaphorical

"地下水に根を張る"

— To spread roots to the groundwater. To be deeply connected to one's foundation.

この文化は、地域の地下水に深く根を張っている。

Literary

"地下水の静寂"

— The silence of groundwater. Describes a profound, deep quietness.

夜の森は地下水の静寂に包まれていた。

Poetic

Easily Confused

地下水 vs 井戸水

Both refer to water from the ground.

Idomizu is water specifically from a well (human-made). Chikasui is the general scientific term for all water underground.

この井戸水(idomizu)は地下水(chikasui)です。

地下水 vs 湧水

Both come from the ground.

Yousui is water that has naturally come out to the surface. Chikasui is still underground.

湧水(yousui)の源は地下水(chikasui)です。

地下水 vs 伏流水

Both are underground water.

Fukuryuusui is specifically the water flowing under a riverbed. Chikasui is all water in the ground.

伏流水(fukuryuusui)は地下水(chikasui)の一種です。

地下水 vs 浸出水

Both are water moving through the ground.

Shinshutsusui usually refers to contaminated water leaking from a landfill or site. Chikasui is the natural resource.

浸出水(shinshutsusui)が地下水(chikasui)を汚染する。

地下水 vs 天然水

Both are natural water.

Tennensui is a broad term for any natural water (often bottled). Chikasui is the specific geological term.

この天然水(tennensui)は、地下水(chikasui)をボトリングしたものです。

Sentence Patterns

[Place]には地下水があります。

山には地下水があります。

地下水が[Adjective]ので、[Result]。

地下水がきれいなので、美味しいお酒ができます。

地下水を[Verb]ために、[Action]。

地下水を守るために、ゴミを捨てないでください。

地下水の[Noun]が問題になっている。

地下水の汚染が問題になっている。

[Cause]によって地下水が[Verb]。

大雨によって地下水が濁った。

地下水の[Noun]を[Verb]必要がある。

地下水の流動を調査する必要がある。

[Noun]の観点から地下水を[Verb]。

環境保護の観点から地下水を管理する。

地下水の[Noun]に伴い、[Complex Result]。

地下水の水位低下に伴い、地盤沈下が加速している。

Word Family

Nouns

地下水位 (chikasui-i) - groundwater level

地下水脈 (chikasui-myaku) - groundwater vein

地下水法 (chikasui-hou) - groundwater law

地下水汚染 (chikasui-osen) - groundwater pollution

Verbs

地下水化する (chikasui-ka suru) - to become groundwater (rare)

地下水を汲む (chikasui wo kumu) - to draw groundwater

Adjectives

地下水的な (chikasui-teki na) - groundwater-like (metaphorical)

井戸 (ido) - well

地層 (chisou) - geological layer

浸透 (shintou) - infiltration

涵養 (kanyou) - recharge

帯水層 (taisuisou) - aquifer

How to Use It

frequency

Common in news, science, agriculture, and high-end culinary discussions.

Common Mistakes

Using 地下水 when you mean tap water. → 水道水 (suidosui)
Tap water is processed and delivered through pipes, while groundwater is a natural resource in the earth.
Saying 地下水道 to mean groundwater. → 地下水 (chikasui)
地下水道 (chikasuidou) means sewers or drainage systems. Adding 'dou' changes the meaning completely.
Pronouncing it as 'chikamizu'. → chikasui
In compounds, 水 is usually read as 'sui' (On-yomi), not 'mizu' (Kun-yomi).
Using 地下水 for a natural spring you are visiting. → 湧水 (yousui)
Once groundwater reaches the surface naturally, it's called spring water (yousui).
Forgetting the particle 'no' in 'chikasui pollution'. → 地下水の汚染 (chikasui no osen)
Japanese requires a particle to link two nouns acting as a single concept like this.

Tips

Use 'no' for attributes

Always link 地下水 to its properties using 'no', like '地下水の水質' (water quality of groundwater).

Sake connection

Mentioning 'chikasui' when talking about sake will make you sound knowledgeable about Japanese culture.

Avoid 'swee'

Keep the 'u' and 'i' in 'sui' separate and clear. It's 'su-i', not 'swee'.

Chika vs Chijou

Remember 地下 (chika) is underground, while 地表 (chihyou) is surface. Don't mix them up!

Break it down

地(Earth) + 下(Below) + 水(Water). The logic is perfect for memorization.

Construction context

In construction, 'chikasui' is often a problem to be managed (drainage/pumping).

Pollution terms

Pair it with '汚染' (osen - pollution) to discuss environmental news.

Drinking water

For water you drink, 'tennensui' or 'idomizu' is more common than 'chikasui'.

Compound nouns

Look for 'chikasui' in longer compound words in newspapers; it's almost always the first part.

Formal reports

In formal writing, use '地下水の採取' instead of '地下水を出す' for 'extracting groundwater'.

Memorize It

Mnemonic

Think of a 'Subway' (Chika-tetsu) but instead of a 'Train' (Tetsu), it's 'Water' (Sui). Chika + Sui = Subway Water = Groundwater.

Visual Association

Imagine a clear blue river flowing through a dark brown tunnel deep under a green field. The word 'CHI-KA' is written on the soil, and 'SUI' is written on the water.

Word Web

井戸 (Well) 土 (Soil) 雨 (Rain) ポンプ (Pump) きれい (Clean) 汚染 (Pollution) 地層 (Layer) 飲み水 (Drinking water)

Challenge

Try to find three different news articles in Japanese that mention '地下水'. One should be about a food product, one about pollution, and one about construction. This will show you the three main ways the word is used.

Word Origin

The word is a Sino-Japanese compound (Kango). It was likely standardized during the Meiji era when Western geological terms were translated into Japanese using kanji combinations that logically described the concept.

Original meaning: Water (水) that is under (下) the earth (地).

Japonic / Sino-Japanese (Kango).

Cultural Context

Be careful when discussing groundwater pollution in specific Japanese towns, as it can be a sensitive local political or health issue.

In English-speaking countries, groundwater is often a purely technical or agricultural term. In Japan, it has a stronger connection to high-end culinary traditions (sake, tofu, tea).

The city of Kumamoto (known as the City of Water). Fushimi in Kyoto (famous for sake made from local groundwater). The 'Water Cycle Basic Act' of Japan.

Practice in Real Life

Real-World Contexts

Environmental News

地下水汚染の疑い
水質基準の超過
浄化作業の開始
住民への説明会

Agriculture

地下水で灌漑する
水不足の影響
井戸の掘削
作物の成長

Cooking / Brewing

仕込み水に地下水を使う
まろやかな口当たり
ミネラル分が豊富
秘伝の水源

Construction

地下水の遮断壁
排水処理
地盤の安定性
掘削中の出水

Disaster Preparedness

災害用井戸の登録
断水時の利用
地下水の備蓄
ハザードマップの確認

Conversation Starters

"この辺りの地下水は飲めるんですか？ (Is the groundwater around here drinkable?)"

"最近、地下水の汚染がニュースになっていましたね。 (Recently, groundwater pollution has been in the news, hasn't it?)"

"美味しい日本酒には、良い地下水が欠かせないそうですよ。 (I heard good groundwater is indispensable for delicious sake.)"

"あなたの国では、地下水をよく使いますか？ (In your country, do you use groundwater often?)"

"庭に地下水の井戸を掘るのは高いんでしょうか。 (Is it expensive to dig a groundwater well in the garden?)"

Journal Prompts

もし自分の家の地下から美味しい地下水が湧き出たら、どうしますか？ (If delicious groundwater bubbled up from under your house, what would you do?)

地下水汚染を防ぐために、私たちが日常生活でできることは何でしょうか。 (What can we do in our daily lives to prevent groundwater pollution?)

日本の「名水」を訪ねる旅について書いてください。 (Write about a trip to visit Japan's 'famous waters'.)

地下水と水道水、どちらが大切だと思いますか？その理由も教えてください。 (Which do you think is more important, groundwater or tap water? Please give your reasons.)

未来の世代のために地下水を守る責任について、あなたの考えを述べてください。 (State your thoughts on the responsibility to protect groundwater for future generations.)

Frequently Asked Questions

10 questions

Not necessarily. While many people in Japan drink 'idomizu' (well water), which is a form of groundwater, it must be tested for bacteria and chemical pollutants. In rural areas, it's common, but in cities, it's often used only for gardening or industrial cooling because of the risk of contamination.

地下水 (chikasui) is the general term for groundwater. 井戸水 (idomizu) is water drawn from a well. You use 'chikasui' when talking about the environment or science, and 'idomizu' when talking about the water you are using at home.

It is '地下水汚染' (chikasui osen). This term is very common in news reports and environmental discussions in Japan.

Sake is about 80% water. The minerals in the groundwater (chikasui) affect the fermentation process and the final flavor. Soft groundwater makes soft sake, while hard groundwater makes a sharper taste.

It's usually the other way around. Earthquakes can change the flow or level of groundwater. However, injecting water into the ground (fracking) can cause minor seismic activity, but this is less common in Japan than in other countries.

It means 'groundwater level.' It is the depth at which the soil is completely saturated with water. Monitoring this is crucial for construction and flood prevention.

Yes, there are various local ordinances and the 'Water Cycle Basic Act' (水循環基本法) that provide a framework for managing groundwater as a public resource.

You say '地下水を汲み上げる' (chikasui wo kumiageru). The verb 'kumiageru' specifically means to pump or scoop up.

It is '伏流水', a type of groundwater that flows through the gravel under a river. It is often very pure because it has been filtered by the earth.

Yes, it is a basic B1 level word. You will hear it in news, school, and when discussing nature or the environment.