How do I install this sump basin?

Question

I have 110 year old house. The basement concrete floor was poured on the dirt and the sump well was an integral part of the floor. Thus the only way water got into the sump was across the floor. I just dug a 1' deep french drain along two inside walls and a much deeper sump well. I'm getting ready to run pipes, tie them into the sump basin, etc.

The sump basin I bought is a lightweight, black corrugated plastic and I'm trying to figure out how to install it. My questions are:

• Does the basin need holes? Seems like it should have holes to accept water down at 24" rather than wait until the water table reaches the 1' french drain
• Do I place anything below the basin or inside it to support the pump (washed stone, etc)
• How do I pick an adequate pump? (there are 50-100 models on Home depot's site)

Answer 1

You could certainly perforate the lower section of the sump basin with small holes (1/4 inch/6mm or less would be my preference, but some might go twice/3 times as large - depends in part what you are bedding it in)

Outside the basin, you'd want washed stone (depending on soil type, possibly filter fabric and washed stone)

Inside the basin, a concrete paver is a suitable pump support. Don't put anything else in there that would make cleaning more difficult.

In my personal experience, pick a submersible sump pump - all the ones I've met have been much more reliable than the pedestal style pumps. To get the most out of whatever pump you buy, don't cheap out on the pipe size - plastic pipe is cheap, no good reason to reduce 2 inch threads to 1-1/2 inch pipe, but I see it all the time - even 1 inch pipe; don't do that - stick with whatever size the outlet on the pump is for best efficiency. And make sure it discharges far enough away from the building - I've met quite a few that pump the same water in circles, from inside to outside, where it comes back inside, to be pumped back outside...

Also, run the pipe straight up as high as it needs to go from the pump, then slope it towards the drain at 1/16 to 1/8 of an inch per foot (or 10mm per meter.)

If you are concerned about pumping rate, you can either try to come up with some sort of test flow (difficult unless the weather cooperates) or simply mount the pump to one side, so that you can add a second pump a few inches higher (use two pavers) if the first proves inadequate when the rains come. If you already have a pump in the old sump, start with that and see how it does.

Answer 2

In my opinion, you want to steer clear of pumps from home depot (flotec, rigid). Go to a plumbing supply house and get yourself a 1/3 HP by Little Giant or Zoeller.