I am wondering if I can extend this sump drain (about 4 foot long and ends 8-10 inches over the ground) through an underground PVC run about 30 feet (about a 4 foot drop from house to valley) to exit into the valley at the back of my property.

As you can see, there is a nice 6-8 inch deep trench about 3 feet long from years of this running and the previous owner really not taking care of it. There are a few concrete tiles tossed in there I am guessing to try and slow the erosion.

Is is OK to extend the sump drain and run it under ground about 30 feet before the PVC would come out of the ground and drain?

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2 Answers 2


First of all, it's a very good idea to get the water away from the house; in general you don't want any pooling or draining water around your foundation. The farther away you have sump pumps, eaves troughs, etc going, the better.

You'll want to check the total discharge head of the pump before you do this. Pump performance is rated in terms of both volume (eg, gpm) and pressure (measured as head). The higher the head, the lower the volume. If you're already at the limit of the pump, then there is a danger it will no longer keep up with incoming water.

The head is a measure of the static discharge head (vertical distance between the liquid level and the discharge outlet) plus friction loss from the pipe itself. There should be at the least a rating for your pump model, and often there are curves that show the flow rates for different amounts of head.

I'd actually suggest avoiding that problem, and instead, running a drainage pipe (eg, 6" big-O) from your house to the back of your property. You'd then just have the existing PVC drain into that (with an air gap, to prevent water from being siphoned back inside). Be sure to slope the line towards the back of course so it does drain properly.

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  • This looks exactly like what I was thinking about doing. I was also thinking I should add a grate (or chicken wire) to the end of it to keep out any small critters as right now it is a foot off the ground so there is no problem currently but once on the ground there might be.
    – zk.
    Apr 13, 2012 at 17:15
  • I probably wouldn't directly connect the horizontal to the vertical - and certainly not seal it tight - you want to leave an escape route should the horizontal portion get blocked.
    – MikeB
    May 16, 2023 at 12:01

I can't think of any reason why not - and in fact I'd recommend it.

Right now your sump is draining water out right next to the house, which means its seeping back into the ground right against your foundation, which means your sump pump is ultimately pumping at lest some of the same water multiple times.

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