Drains backing up - will it affect my drinking water?

Question

We had -15 below zero weather a few days ago. I did not notice any plumbing problems at the time. However a couple of days ago my toilet starting gurgling and then over flowing. I thought my daughter had put something down it (she may have). Now when flushing it, backs up into the bathtub. At the same time this was happening we were running the dishwasher. I attempted to plunge the toilet but you hear the gurgle in ALL the drains, including the kitchen sink. I also tried force flushing with several gallons of bottled water.

The water is also coming up the bathroom sink drain. As I have an S trap under the kitchen sink, draining through the floor to the basement, I am worried about the safety of my drinking water. There is a call into a plumber but this will take several days to hear from him. I have one of those funny kind of vents in the basement (looks like a plastic tube) and also a clean out in the side yard. My biggest concern in the drinking water safety until this is fixed. We are on city water.

What can I do right now to keep my drinking water safe, protect my house, and minimize my overall expense and trouble?

Answer 1

Blocked drains have no effect on the safety of your drinking water, if you don't contaminate the supply with the backed up drains.

Any remotely "modern" faucets (and other plumbing) are designed to prevent such contamination - they terminate above the level of the sink, so the end of the faucet cannot be submerged. Those which can be submerged or have a hose attached are outfitted with vacuum breakers to prevent backflow.

Even with a submerged faucet end (from an old faucet), there would ALSO have to be a loss of pressure on the city water to cause any backflow into the supply system.