Plumbing issues - two different backflow valves failing!

7 Replies

One of my properties is in a combined sewer system. Whenever it has rained, and it has rained extensively here in PA/NJ, the original backflow valve installed was failing.

I had my plumber who I trust install a new backflow valve; they removed all the old pipe, brought in new PVC and checkvalve (installed right over the sump pump by the edge of the basement). This was Monday.


My tenant came home today after a few days away and some terrible rain, and said the basement was worse than ever. He said its now leaking by the newly installed backflow valve.

I'm lost on this one. My plumber mentioned it could be a city problem, but there has to be some recourse to prevent this, no?

Any help would be appreciated.

@Joe P. This is confusing , are you having a problem with the sewer ? Or are you having a problem with a sump pump ?  Never heard of a combination sewer sysyem .   It doesnt sound like a backflow valve , ( they are for pressure potable water )  sounds more like a check valve 

So a new check valve was installed to replace the existing check valve, which was definitely leaking.

I went to the property today and all the new piping, fittings, and check valve are bone dry.

I think my issue is...water...and lots of it...is making its way into the basement somehow when there is heavy rain. This appears to be seeping up from the floor, but I've yet to catch it in the act. The walls are dry but the floor is wet.

@Joe P. you need a french drain it sounds like. I'm a little north of you in Allentown and a month ago when we had some heavy rain I was doing some work in our old house soon to be rental.  I caught water seeping through a small crack in the concrete. And its almost unnoticeable but for the effects it has over time. Aside from this one spot the basement has a french drain system that catches the water before it rises through the floor and directs it to the sump pit. I heard the pump running about every 5 minutes. That being said maybe your current pump may just not be able to keep up, maybe a second pump too? 

Combined sewer is having sanitary waste and storm water being served by the same waste piping system. if you have a check valve installed on the sewer main it's only going to stop water from flowing back from the street. So if the city sewer is backed up and full of water, the flap on the check valve will not open and let water from the house side drain. Kinda confusing how you mentioned the sump pump, if your sump pump is draining into the house side of the sewer (behind check valve). Then when the city side is backed up that sump pump water has no where to go besides the lowest fixture. Sump pumps should not be installed on a sewer main. Also see if you're rain leaders go into your house on some old buildings with combined sewers they did. So when the streets backed up and it's raining hard the flap on check valve won't open and all the rain water could still be trying to drain through your lowest fixture. 

We had a home we rehabbed that was on a very slight slope towards the road but enough for the basement to be constantly wet after heavy rains & especially during the spring thaw. Much like yours the water was literally seeping up through the hairline cracks, but our sump pump was running constantly but spewing it out on the 'upstream' side of the natural flow. I redirected the sump pump flow to well beyond the 'downstream' basement wall & that solved the issue. My old basement flooring was probably minimum depth cement & the hairline fractures, because of that, were enough for the hydrostatic pressure to literally push water up onto the surface. I bet my weeping tile was not correctly installed (if at all).

@Pat L. the area by the sump is bone dry. The water is leveling at its lowest point in the basement and isn't high enough to hit the sump, apparently. So its just a puddle with an idle sump.

I'm wondering if a french drain is needed as @Justin Brown indicated?

Best solution would be a sump pump at the lowest point. Any French drains we have installed still had to flow into the sump to be expelled.

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