Sanitary Sewer System Smoke Testing

September 28, 2018 6:28 PM

I live in a complex built in the mid 1980s. It's single-family houses. Own, and have lived here for nearly a decade. We often have had "weird smells" in the house. Two or more times, the local sewer company came with a big truck and did some sort of pressure treatment.

One time when they were doing this we had massive bubbling through our ground floor toilet (enough bubbling to spray water out of the toilet) and I ran out to ask them to stop.

They said "oh, we are using too much pressure" and backed off.

But many other times, something has been "not right" for about 10 years - weird smells, gassing etc.

A few years ago the weird "pumper" truck arrived, and I talked to the people and they said there was a section of sewer with not enough slope, that often got clogged up.


Today, we get this notice: "Sanitary Sewer System Smoke Testing" that they are going to blow "harmless white smoke up the sewers" to try to diagnose the problems.

It sounds good, like they are finally admitting there is a problem.

Questions:

1. Given that at least one time, they "oopsed" and shot sewer gasses up through our downstairs toilet, do you think I need to be home for all of this testing (5 days in length).

2. Is there anything I can do to help them?

posted by soylent00FF00 to Home & Garden (6 answers total)

Here's a FAQ about smoke testing.

There have been a couple of times in the past 20 years when the city has been working on the sewers in my neighborhood and managed—either by too much pressure or too much vacuum—to blow/slurp the water out our toilets' traps. It mostly resulted in a terribly sucking noise, as if a hellmouth had opened beneath the house. I didn't notice a significant buildup of sewer gas funk at the time, but it's possible it could happen over five days. Forewarned, I'd make sure all of my traps were well wetted—particularly little-used ones, like a basement utility sink, that might have dried-up from disuse.
posted by mumkin at 6:47 PM on September 28, 2018

Answer - if you can be there, you should, just to be present, but of course 5 days is a lot of time. But there isn't anything that I can think of that you can do to help them do what they need to do.

The "local sewer company" is a contractor, but it is the city or other municipality that is responsible to keep the system intact. It sounds like there is a blockage downstream from your location, and that they are trying to find out where it is.

If you want to investigate, you could make an FOI request to the local authority for any documents regarding sewer complaints and sewer testing. The results may be interesting.
posted by megatherium at 6:52 PM on September 28, 2018 [1 favorite]

When they did smoke testing in my neighborhood, they pressurized the sewer with smoke and looked for smoke coming from downspouts and other places. They were looking for illegal sewer taps. They want to keep storm water out of the sewage to reduce sewer processing volumes.
posted by H21 at 7:41 PM on September 28, 2018 [2 favorites]

Your vent stack is usually a 4" pipe running from your sewer to the roof. Vents from all your fixtures (toilets, sinks) connect to this vent stack. For pressure to build up enough to blast water out of your toilet, it seems like your vent would need to be clogged. Do your drains gurgle when you flush the toilet?
A plumber could check this.
posted by H21 at 9:47 PM on September 28, 2018 [3 favorites]

ya drain issues is it cast iron pipes? if so they clog up
posted by patnok at 6:32 PM on September 29, 2018

Response by poster: Thanks for all the wonderful replies!

Turns out, either the smoke folks didn't show, or they came and went without anyone noticing. Someone was home almost the entire time so we are thinking maybe they never did our area.
posted by soylent00FF00 at 6:37 PM on October 6, 2018