Finally got to the bottom of the drainage nightmares in our Madison flip

I dealt with a 1950s ranch in Waukesha that had the exact same issue with a basement "renovation." The flippers used a cheap Liberty Pumps 260 series but didn't even bother to secure the float switch properly. Every time the laundry ran, the basin whould overflow becuase the float got pinned against the side of the pit by a stray piece of PVC scrap they left behind during the build. Taking that lid off is the worst part of the job, especally with that sewage smell. When I pulled mine, I found they hadn't even primed the glue joints on the 2-inch discharge line. I ended up swapping the whole unit for a Zoeller M53 and installing a silent check valve—the kind with the clear housing so you can actualy see if the flap is moving. It made a huge difference in the noise level in the guest room right above the basin.

Dealing with construction debris in the impeller is just lazy on their part. I learned the hard way to keep a shop vac nearby just to suck out the bottom of the basin whenever the lid is off, just in case there's more gravel or tile shards hiding down there. It's frustrating having to redo work you already paid for in the purchase price, but at least now you know it's done right.

My expirience with a flipped 1960s bungalow near Monona was similar, but the issue wasn't just debris. The crew had installed a cheap check valve vertically without a union, making it nearly impossible to service without cutting pipe. Even worse, they vented the basin into the stack using a simple air admittance valve hidden behind a drywall patch. Since those pumps move a lot of volume quickly, the AAV couldn't let air out fast enough, causing the basin to air-lock and back up into the basement shower pan.

I ended up ripping out the drywall and running a dedicated 2-inch PVC vent up thru the roof to clear the pressure. While I was at it, I swapped their basic unit for a Zoeller M267. It’s a heavy cast-iron beast compared to those plastic-housed units flippers love beacuse they're cheaper at the big box stores. If your basin is still smelling, check if they actually tied the vent into the main stack or if they just took the easy way out with a Studor vent. Those things are magnets for sewer gas leaks when they're under constant pressure from a pump cycle.

This sounds like a total nightmare. I'm still learning how all this works, but I'm curious about that 'silent' check valve you mentioned. Does it realy stop that loud thudding sound every time the pump finishes? Our basement bathroom is right under the living room, and the noise is driving me crazy. Also, since I'm new to this, is there a specific way to tell if my pump is a 'cheap' one or a good brand like that Zoeller without pulling the whole thing out again?

Oh man, reading this is making me so hyped to finally start my own DIY plumbing projects! I'm totally obsessed with how you guys just jump in and fix things yourself. Speaking of Madison though, I keep hearing about those old houses having crazy foundation issues too. While you were down there messing with the ejector pump, did you notice if they used any of that wierd spray-on waterproofing on the walls? I'm trying to figure out if that stuff actualy works or if it's just more flipper magic!