Pod zlewem jest mały przeciek, bo rura jest już stara.

Because the preposition pod can take different cases depending on the meaning.

In this sentence, pod zlewem means under the sink in a static location, so pod takes the instrumental case.

• zlew = sink
• zlewem = instrumental singular of zlew

A useful contrast:

• pod zlewem = under the sink (location)
• pod zlew = to under the sink / placing something under the sink (movement toward a place; this is much less common in practice, but it shows the case contrast)

So here, because nothing is moving, pod zlewem is correct.

Zlewem is in the instrumental singular.

The base noun is:

• zlew = sink

After the preposition pod when it means location, Polish uses the instrumental, so:

• pod zlewem = under the sink

This is a very common pattern with location after some prepositions:

• nad stołem = above the table
• przed domem = in front of the house
• między krzesłami = between the chairs

Polish often leaves out to be in the present tense when saying that one thing is another thing, especially in simple identity statements.

For example:

• To mój brat. = This is my brother.

But in sentences of existence or location, jest is very common and natural:

• Pod zlewem jest mały przeciek. = There is a small leak under the sink.
• Rura jest stara. = The pipe is old.

So here, jest is needed because the sentence is saying:

1. something exists in a place
2. the pipe has a property

Polish word order is flexible, but different orders sound more natural in different contexts.

Pod zlewem jest mały przeciek is a very natural way to present new information:

• first the place: under the sink
• then what is there: a small leak

This works a lot like English There is a small leak under the sink, except Polish does not need a special dummy word like there.

You could also hear:

• Mały przeciek jest pod zlewem.

But that sounds more like you are contrasting or emphasizing the leak itself, not just introducing it naturally.

Przeciek means a leak, especially when something is leaking through or from somewhere.

In everyday home-repair contexts, przeciek works well for a leak in plumbing, a roof, etc.

Wyciek also means leak, but it often suggests a spill, outflow, or escape of a substance, and it is also common in more technical or formal contexts:

• wyciek gazu = gas leak
• wyciek danych = data leak

For a small household plumbing problem, przeciek sounds very natural.

Because przeciek is a masculine noun, so the adjective must agree with it.

• mały = masculine singular
• mała = feminine singular
• małe = neuter singular

So:

• mały przeciek = a small leak

This is standard adjective-noun agreement in Polish:

• stara rura = an old pipe
• mały przeciek = a small leak

Because rura is a feminine noun, so the adjective must be feminine too.

• rura = pipe
• stary = old (masculine form)
• stara = old (feminine form)

So:

• stara rura = an old pipe
• rura jest stara = the pipe is old

This is another example of adjective agreement.

Bo means because.

It is very common in everyday spoken and written Polish and sounds natural here:

• Pod zlewem jest mały przeciek, bo rura jest już stara.

You can also use ponieważ, which also means because, but it is usually a bit more formal or neutral in tone:

• Pod zlewem jest mały przeciek, ponieważ rura jest już stara.

In ordinary conversation, bo is often the most natural choice.

Już usually means already, but in many sentences it adds the sense of by now, as it is now, or no longer new.

So rura jest już stara suggests:

• the pipe has reached the point where it is old
• this age is now relevant to the problem

It sounds more natural than just rura jest stara in this context, because it implies that the pipe’s age has become an issue.

Compare:

• Rura jest stara. = The pipe is old.
• Rura jest już stara. = The pipe is already old / The pipe is getting old now / The pipe is old by this point.

Grammatically, Polish word order is flexible enough that this may be understood, but it sounds unnatural in normal speech.

The most natural versions are:

• Pod zlewem jest mały przeciek.
• Mały przeciek jest pod zlewem.

Polish does allow unusual word order for emphasis, poetry, or contrast, but learners should usually stick to more standard patterns unless they know why they are changing the order.

Polish does not need a dummy subject like English there.

English often says:

• There is a leak under the sink.

Polish simply says:

• Pod zlewem jest mały przeciek.

The idea of existence is carried by jest plus the context. This is very normal in Polish.

Yes. In everyday usage, pod zlewem often refers to the whole area under the sink, including the cabinet or space below it, not just the exact physical underside of the sink basin.

So in a household sentence like this, a Polish speaker would normally understand it the same way an English speaker understands under the sink.

A few useful pronunciation notes:

• pod = like pot but with a final d that may sound somewhat devoiced in natural speech
• zlewem: the beginning zl- can feel difficult for English speakers; try zleh-vem
• przeciek: roughly pshe-chyek
• rura: roo-ra
• już: roughly yoozh
• stara: sta-ra

A few sound tips:

• rz in przeciek sounds like the zh sound in measure
• cie in przeciek is a soft sound, something like chye
• ż in już is also the zh sound

A rough full pronunciation guide:

• Pod zlewem jest mały przeciek, bo rura jest już stara.
• pot ZLEH-vem yest MAH-wih PSHE-chyek, bo ROO-ra yest yoozh STA-ra

Polish does not have articles like a/an and the.

So rura can mean:

• a pipe
• the pipe

The exact meaning comes from context.

In this sentence, English naturally uses the pipe because the speaker probably means the specific pipe under the sink. Polish does not need a special word for that; rura is enough.

This is one of the biggest differences from English:

• rura can mean either a pipe or the pipe
• przeciek can mean either a leak or the leak, depending on context