Learn Hardcore Polish: Co miesiąc płacimy czynsz, rachunek za prąd i za gaz. - Every month we pay rent, the electricity bill and the gas bill.

Co miesiąc = every month / once a month (very natural, standard way to express regularity).
Każdy miesiąc = literally each month. It’s possible, but in this context it sounds a bit heavier or less idiomatic.

For regular, repeated actions with time units, Polish very often uses:

co tydzień – every week
co miesiąc – every month
co rok – every year

So Co miesiąc płacimy… is the most natural phrasing here.

Why is miesiąc in the singular after co? Why not co miesiące?

With co meaning every/per, Polish always uses the singular:

co dzień – every day
co tydzień – every week
co miesiąc – every month
co rok – every year

Using the plural (co miesiące) is ungrammatical in this pattern. Think of co + singular time word as a fixed structure.

What case are czynsz, rachunek, prąd and gaz in?

They are all in the accusative case (biernik), because they are direct objects of the verb płacimy (we pay).

płacimy (kogo? co?) czynsz – we pay (what?) the rent
płacimy rachunek – we pay (what?) the bill
rachunek za (co?) prąd – a bill for (what?) electricity
rachunek za (co?) gaz – a bill for (what?) gas

For masculine inanimate nouns like czynsz, rachunek, prąd, gaz, the accusative form is the same as the basic dictionary (nominative) form, which is why they don’t visibly change.

Why is there no word for “the” in czynsz, rachunek za prąd i za gaz?

Polish has no articles (a, an, the). Whether it means “a rent” or “the rent” is understood from context.

płacimy czynsz can mean we pay rent or we pay the rent.
rachunek za prąd can be an electricity bill or the electricity bill.

If you really need to specify, you use other words (like ten – this, tamten – that), but in everyday sentences like this, you simply drop articles completely.

Why is it płacimy czynsz but rachunek za prąd i za gaz? Why not czynsz za mieszkanie?

You actually can say czynsz za mieszkanie (rent for the flat), but here czynsz on its own is clear enough in context, so the extra za coś is not needed.

With rachunek, however, Polish normally specifies what the bill is for:

rachunek za prąd – the bill for electricity
rachunek za gaz – the bill for gas
rachunek za wodę – the bill for water

So:

płacimy czynsz – we pay (the) rent
płacimy rachunek za prąd – we pay the electricity bill

Both płacić czynsz and płacić rachunek za coś are fixed, natural patterns.

Why is the preposition za used in rachunek za prąd i za gaz?

With bills and payments, Polish uses za to mean “for”:

rachunek za prąd – bill for electricity
rachunek za gaz – bill for gas
rachunek za internet – bill for the internet
płacić za bilet – to pay for a ticket

So za here introduces what the bill is for (or what you’re paying for).

Do we really need to repeat za in za prąd i za gaz? Could it be rachunek za prąd i gaz?

You can say both:

rachunek za prąd i za gaz – very clear and quite common
rachunek za prąd i gaz – also correct and natural

Repeating za (za prąd i za gaz) can sound a bit more careful or emphatic, but it’s not required. Both versions are idiomatic.

Why is it rachunek za prąd i za gaz (singular) and not rachunki za prąd i za gaz (plural)?

Both are possible; they just emphasize slightly different things.

rachunek za prąd i za gaz
– one combined bill that covers both electricity and gas
– or loosely: “the bill(s) for electricity and gas” in general
rachunki za prąd i za gaz
– clearly refers to two types of bills, often two separate payments

In practice, people often use the singular loosely for “the bills” in general, especially in casual speech. Context usually makes it clear.

Why is it płacimy, not płacę or płacisz?

Because the subject is we.

Płacić (to pay), present tense:

(ja) płacę – I pay
(ty) płacisz – you (sg.) pay
(on/ona/ono) płaci – he/she/it pays
(my) płacimy – we pay
(wy) płacicie – you (pl.) pay
(oni/one) płacą – they pay

So płacimy is 1st person plural – “we pay”.

Why is there no my (“we”) in the sentence? Could we say My co miesiąc płacimy…?

Polish usually drops subject pronouns (ja, ty, my, wy, etc.) because the verb ending already shows the person and number.

Płacimy czynsz = We pay the rent. (my is understood from -imy)
Idziemy do domu = We are going home.

Adding my is possible, but it changes the nuance:

My co miesiąc płacimy czynsz… – puts extra emphasis on we (e.g. We pay it every month, maybe in contrast to someone else).

In a neutral sentence like yours, płacimy without my is more natural.

Why is it płacimy and not zapłacimy?

This is about aspect (imperfective vs. perfective verbs).

płacimy – imperfective, focuses on the ongoing or repeated action:
Co miesiąc płacimy… – Every month we pay…
zapłacimy – perfective, focuses on a single, completed payment in the future:
Jutro zapłacimy rachunek. – We will pay the bill tomorrow.

For habits and regular actions (every month, every week, etc.), Polish uses the imperfective form: płacimy.

Could we also say Co miesiąc płacimy za czynsz, za prąd i za gaz? Is that correct?

Yes, it’s grammatically correct:

Co miesiąc płacimy czynsz, rachunek za prąd i za gaz.
Co miesiąc płacimy za czynsz, za prąd i za gaz.

Differences:

With czynsz it’s more common to say simply płacić czynsz (without za).
płacić za prąd / za gaz is also very natural.

So your alternative is fine, but the original version sounds slightly smoother and more idiomatic: płacimy czynsz, rachunek za prąd i za gaz.

Is the word order fixed? Can I say Płacimy co miesiąc czynsz, rachunek za prąd i za gaz?

Word order in Polish is flexible. These are all correct:

Co miesiąc płacimy czynsz, rachunek za prąd i za gaz.
Płacimy co miesiąc czynsz, rachunek za prąd i za gaz.
Czynsz, rachunek za prąd i za gaz płacimy co miesiąc.

The most neutral and common is probably the original: Co miesiąc płacimy…, but moving co miesiąc or the objects for emphasis is perfectly fine. Context and intonation decide which part is stressed.