"Slått av" wouldn't work here?
Not really, since the water isn't switched off. Electricity could be "slått av" in an empty house, but you would likely say it is "stengt av" if you had no electricity due to multiple unpaid bills.
Although I agree with this, I put "slo av" and it appeared to be a correct answer. I believe the past of "slå" is "slo".
Is it possible to say, "De stengte vannet av"? Takk!