Sump pump running, flush toilet and water comes up into bathtub

Hello and Help! The water from our washing machine is routed into our sump pump pit which then ejects that water to the main pipeline. For years, every time we wash clothes and the pump starts ejecting the water, the toilet gurgles several times and almost all of the water gets sucked out of the bowl. Rarely, water would also simultaneously back up into the bathtub. We think the previous owners had what appears to be some kind of check valve installed in the pipe that connects the pump to the main line. Anyway, there have been one or 2 occasions where if someone just happened to flush the toilet at the exact same time the pump started running, it would flush but come right back up into the bathtub. Downstairs in the basement, water would be leaking from the pipe that comes out of the bottom of the toilet at the same time and spraying all over the basement floor.

All this came to a head this past Father's Day weekend when everything seemed to be backed up and we couldn't shower because the water wasn't draining at all, and we could flush the toilet but it would just go straight to the bathtub. We had our main line snaked with a huge auger and there were no blockages until it reached the street. Once that was cleared, we didn't seem to have any issues. We washed clothes and watched the water in the toilet - it would move as though there was still some suction going on, but it would never gurgle. Well, after a few days, we were back to the gurgling every time we washed clothes. This morning we happened to flush the toilet right as the pump started running and same thing as before - it all backed up into the bathtub and you could hear a loud "swishing" in the pipes under the bathroom like the water was trying desperately to find somewhere to go.

So, I say all of that to say this. Everyone we talked to said that these issues were likely due to a blockage in our main line. Well, we just had our line snaked and cleared out, so that's obviously not the issue. Thoughts? Suggestions? Opinions? I welcome anything because we are ready to pull our hair out. THANKS!

 

Is the pump chamber vented?

 

I'm sorry to say that I am not 100% certain. How can we tell? We are not avid do-it-yourselfer's (obviously!)

 

I think there should be two pipes going into the chamber. one ties into the stack higher up or out thru the roof.

 

Ok I'll check this evening and post again. Thanks Nealtw!

 

You may want to force water down your vent pipes with a garden hose and one of these

http://www.acmehowto.com/plumbing/clogs/how-to-use-blow-bag.php

to make sure they are clear.

But, have people stationed downstairs to make sure the water you are forcing into your piping is not going somewhere undesirable.
I had the opposite, using one of these to clear a disposal clog - chopped veggies were landing on my roof from the vent pipe so I had to use an inflatable bladder to temporarily clog the vent so the water pressure would get high enough.

 

nealtw,

We only see one pipe running out of the sump pump, and it runs upward to the basement ceiling, then it curves and runs parallel to the ceiling for 2-3ft and then connects to the main line. In that 2-3ft section, there's some kind of check valve - or at least we're assuming that's what it is. I can post pics tonight of the entire set up to give you a clear idea.

 

Post some pics of how it is hooked up.

 

Ok guys, here are some pics that show the sump, and how it's attached to the main line.

 

Here's the last pic again, except with markings. I put a blue line on the pipe that belongs to the sump pump. In red I circled what we think might be a check valve, or maybe it's a "cheater valve" like Bud said.

 

It sure sounds like a vent problem but the fitting where the pipe joins the other pipe dosn't appear to be a "Y" fitting
I think it is more a problem with the fitting at the end , that does look like a check valve.

 

Post #10, first photo, check valves for sump pumps are always vertical(?) and close to the pump.

Otherwise, the one gallon or so in the output pipe would re-enter the sump when the pump stops and could cause the pump to cycle on and off forever, depending on the cross-sectional area of the sump and the float level switch settings.

 

BTW, the toilet needs a new wax ring, it should not allow water to leak to the basement, now that it has it will allow sewer gas to enter the house even if it dosn't appear to leak.

 

Bud, I think it is the fitting not directing the water in the right direction and the water just fills the pipe both ways, plugging it until the pump stops.

 

In my small sump, one gallon equals a ~2" level shift. My output pipe is 8' of 5/8" ID hose holding about 0.1 gallon so no check valve for me.

 

Thanks guys for taking the time to respond. I'll get the details on the venting and such and post back in the next day or two. Thanks again -- much appreciated! We just might figure out this rascal after all.

 

I applaud your ambition

Some projects are like these
http://www.google.com/search?client=safari&rls=en&q=nested+dolls&ie=UTF-8&oe=UTF-8
as you solve each problem, a new one pops up.