Taloyhtiössä on toinenkin vesikatko ensi kuussa, joten täytän vesipullot valmiiksi.

Taloyhtiössä is taloyhtiö (a housing company / condo association) in the inessive case (-ssa/-ssä), which roughly means in.
So taloyhtiössä = in the housing company/building community (i.e., in that apartment building’s association / shared building context).

Finnish often uses an existential (there is/are) structure:

• [place] + on + [thing that exists/occurs]

So Taloyhtiössä on vesikatko is literally In the housing company there is a water outage, i.e. There will be a water cut in our building.

A “have” type structure is possible in Finnish with -lla/-llä (adessive) (e.g., Minulla on… = I have…), but for events happening in a location/community, the existential structure is very natural.

Yes. Vesikatko is a compound:

• vesi = water
• katko = cut / interruption

So vesikatko = water outage / water cut (a planned or unplanned interruption in water supply).

toinen = another / second
The clitic -kin adds the meaning also / as well / yet another depending on context.

So toinenkin vesikatko implies: not only one—there’s another one too, often suggesting mild surprise/annoyance: “another water outage again.”

Without -kin, toinen vesikatko would simply state it more neutrally as a second/another water outage.

toinen can be both:

• second (when counting: first → second)
• another (an additional one)

Context decides. Here, with -kin and the general situation, it reads naturally as another one as well (and also implies it’s not the first time).

ensi kuussa is a common, idiomatic way to say next month:

• ensi = next (upcoming)
• kuussa = in the month (kuu
  • inessive -ssa/-ssä)

seuraavassa kuussa is grammatically possible but sounds more like in the following month and is less common for ordinary “next month” statements.

Finnish uses the inessive (-ssa/-ssä) for many time expressions meaning in/during a time period:

• tänä vuonna = this year (inessive)
• ensi kuussa = next month (inessive)
• maaliskuussa = in March (inessive)

So kuussa literally means in the month.

joten means so / therefore, introducing a result or conclusion.

Finnish typically uses a comma before joten when it connects two clauses:

• …, joten … = …, so …

That’s why you see: ensi kuussa, joten täytän…

täytän comes from täyttää = to fill.
The ending -n marks 1st person singular present tense: I fill / I will fill (Finnish present often covers near-future intention).

So täytän = I’ll fill / I’m going to fill (based on context).

With täyttää, the object choice depends on whether the action is seen as completed or not:

• täytän vesipullot = I fill the water bottles (as a complete set / completely filled)
• täytän vesipulloja = I fill (some) water bottles / I’m filling bottles (indefinite, incomplete, or ongoing)

Here the idea is preparation “in advance,” so the total/complete reading fits: vesipullot.

Also note: in Finnish the plural accusative often looks the same as the nominative plural, so vesipullot is the normal written form here.

Yes, it’s a compound:

• vesi (water) + pullo (bottle) → vesipullo (water bottle)
  Plural nominative/accusative: vesipullot = water bottles.

Compounds are extremely common in Finnish, and the first part often appears in a basic form (like vesi-) attached to the second part.

valmiiksi means in advance / ready / prepared (so that it’s ready).

It comes from valmis (ready) in the translative form (-ksi), which often expresses becoming/ending up as a result:

• Teen sen valmiiksi = I’ll get it done / make it ready
• täytän vesipullot valmiiksi = I’ll fill the bottles so they’re ready beforehand

A close alternative in meaning is etukäteen (in advance), but valmiiksi emphasizes the “ready state” result.