I live in area without sewers, so we depend on swales and drainage ditches when it rains. My basement sump pump outlet is in the ditch in front of the house, but it's a couple of inches below grass level. Often the ditch fills over the outlet during heavy rain, which can make the sump pump fall behind and bam, water in the basement.

I'm thinking of putting an upside-down J pipe on the outlet so the water actually comes out of it at above ditch level. I'm pretty sure I'm not even close to maxing out either the rise or run specs on the sump pump even if I do this.

Is this plan stupid? Am I better off just installing a stronger pump? If I go that route, how do I know how powerful a pump the buried outlet pipe can withstand? Is there even a risk of bursting it since it's buried and so supported on all sides by earth?

  • "swale", I think.
    – keshlam
    Jul 4, 2014 at 6:10

3 Answers 3


You should not add an upward bend to the pipe, as that will more likely lead to water always sitting in the pipe.

Instead you should add a check valve (one way valve) to the line. This will allow the pump to push water out, while preventing ditch water from flowing back in.

If the pump is strong enough, it should be able to push water into the ditch even when it's full. Unless the outlet is pointed upstream, in which case you should redirect the pipe downstream.

  • 1
    Some sump pumps may require that when adding a check valve there must be a small hole in the pipe between the pump and the valve, to prevent air from being trapped between the bottom of the pump and the check valve. If too much air gets trapped in there, the pump may never build up enough pressure to force the air through the check valve.
    – supercat
    Jan 20, 2015 at 22:35

If the rise on the pump is enough for the additional height of the J, I would think it would be enough to pump despite back-pressure from whatever water is in the ditch... but I may be wrong about that. So you might need a more powerful pump even with the extension.

This sounds to me like the first step should be to make sure the property is graded so water naturally tends to run away from the foundation, then make sure the pump's outlet also tends to run downhill away from the house...

My own setup -- which I admit is entirely ad-hoc -- starts with a pump that lifts water to about 3' about ground level and out through the wall using PVC pipe. That ends in a downward bend and a fitting which flex hose connects to -- and the flex runs the water about 20 more feet away from the house. (This replaces a setup which required that I open a basement window to run flex hose from the pump to outside, with about the same rise/fall distances. I decided that if I was going to have a pump at all, I wanted an installation that started working before I was aware there was a problem. Even if I may never need it until the next "hundred-year flood.")


For someone who installs sumps pumps practically every day of the week, a check valve is part and parcel of sump pump's discharge line. We typically install it within the sump and then make sure the discharge line is going up and out and has a pitch away from the house. The crucial area where you don't want water to pool up, is the immediate 5-6'from the house. If you are saying that water pools up within that area and buries the outlet of your current discharge line, and if adding an extension vertically is feasible/functional, then i would go straight up with an elbow, 90 or 45 degree, and up as far as you need but then put a small weep hole on the bottom of the elbow or horizontal piece so that water drains out from the vertical extension and ice doesn't form in the below freezing circumstances. If you ever need more info on basement waterproofing and french drains/sump pumps, hit up my blog on my website. Oh, what size is your sump pump? Hopefully at least a 1/3HP or higher (if it's less, upgrade!).

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