Air in the lines?

[NJSteve]

A very weird thing happened today and I'm hoping someone here can tell me whether I have any reason to be concerned.

I live in a townhouse apartment built in 2002. Aside from having very hard water, all of our plumbing works great and was just checked out less than a month ago. The toilets flush normally, with no clogs. The sinks, the washing machine, and the dishwasher drain without an issue. No gurgling. Nothing.

Today, a plumber was installing a new water heater in the unit next to ours (which has been vacant for a few months). He shut off the main water valve in that unit in order to do the work.

At one point, just as I was flushing the upstairs toilet that's on the adjoining wall, I heard a tremendously loud noise coming from our toilet--as if the world's strongest man were plunging it. This stopped after a few seconds and I lifted the lid to see discolored water, possibly from sediment. I flushed again and it still didn't sound right, but nothing like the first time. Ever since then, it's flushed normally.

I then tried our other toilet. On the first flush, it made a loud banging noise, but it's been normal ever since. Then I started the washing machine. When the water first came out, it seemed like a big puff of air came with it. And the same with the kitchen sink. This was about two hours ago. At the moment, knock on wood, everything in the house seems to be working normally.

We've lived here for five years, and people have lived in that neighboring unit for most of that time, and we've never experienced anything like this. I ran outside and asked the plumber what happened and he was baffled. He said nothing he did could have caused our issue. But it seems a little too coincidental to me.

Is it possible that the plumber's work next door caused some air to get trapped in the system? How does that happen? And, more importantly, does today's weird event suggest that there's a clog or partial clog somewhere in the main line? Do I have to worry that our neighbor's toilet is going to back up in our unit when someone finally moves in?

 

[WorthFlorida]

Yes, air got into the cold water pipe and I've had it happen to me in my own home. I know, it sounds like a bomb went off. About two years ago the water company relocated and replaced the anti backflow device to the water meter. All is good and they leave, first floor all is good, I flush the second floor toilet and scared the crap out of me. The toilet lid actually bounced. In the same bathroom the sink faucets squired some air for a second or two.

Drain wise nothing to do with it. Sometimes when the water is rushed through the pipes to purge it of air, it loosens sediments on the inside wall. It gets into the tank and eventually clears out after a few flushes.

This happen just last Wednesday, I found all my toilets with water splashed all over the underside of the toilet seats and the bowls almost empty. A few days before a truck was working on the septic sewer lines in our neighborhood. At one time a jetter was used. Last Wednesday morning we leave for a three hour drive and I see the truck with an open sewer cover and a submersible pump. When we came home about 8PM is when I saw the water though none on the floor. Whatever he was doing it blew water out of all three toilets including the second floor all from the street.

 

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[NJSteve]

Thank you, WorthFlorida, for taking the time to respond. I feel much better after reading your post. I suspected it had to do with air in the water line based on the involvement of the sink and washing machine. But the sound coming from the toilet was so unbelievably loud--like a bomb, just as you said--that it caused me to question everything! Glad to hear it's nothing to do with the drain line. That would have been so much worse. I guess I'm just puzzled by two things now:

1. How could air that entered the system in the neighboring unit affect us? I didn't think our water lines were connected. Each unit has its own meter and we pay for individual usage.
2. Why was the plumber so perplexed when I asked him what had happened? I wonder if he forgot to open a faucet when he shut off the main valve.

Sorry to hear about what happened to you last Wednesday! Yuck!