Sump Pump Weep Hole – DIY Guide For Location & Installation

A weeping hole or a horizontal vent hole should be drilled into the discharge pipe of your sump pumps if you want to prevent air bounding. Drilling a sump pump weep hole is a must if you want to correct a sump pump airlock if it develops.

It’s easy to drill a weep hole. All you need to do is follow what the procedure that is recommended by the user guide of your pump, and you will be good to go.

In this article, I’m going to talk about why you need a weep hole in sump pumps, sump pump weep hole location, and installation.

What Is A Weep Hole?

Let’s start off with the basics. What is a sump pump weep hole? In short, this is a hole drilled specifically into the discharge pipe to prevent airlocks. If air gets trapped, your pump won’t be able to pump out water.

Why Do You Need A Vent Hole In Sump Pumps?

Weep hole prevents airlock. This happens when you get a huge deluge of water getting into the pit, and the pump starts up, and then the water gets stuck on the pump and gets air trapped in.

That extra air gets into your discharge pipe between the discharge port and the check valve. If you let air stuck in there and it has nowhere to escape via a weep hole, then it will be just trapped in there.

Your pump will be running, humming & pumping, but nothing will come out at the end of the discharge pipe. You are not going to see any water pumping out of there. It can also be disastrous too.

This can cause the water level in the pump to rise up & flood all over the place. When you see your pump humming, but nothing is coming out of the discharge pipe, chances are it is air locked.

And that’s why you need a weep hole in a sump pump. In order to alleviate that, you drill a weep hole.

Where to Drill a Weep Hole?

Now that you know why you need to drill a weep hole, it’s time to look at where you should drill a weep hole. Take a drill bit and drill a hole into the discharge pipe. The location should be about a few inches above the main pump.

I would suggest you drill at a 45-degree angle so that the weep hole is pointing down toward the bottom corner and towards the bottom of the basin. That will also help eliminate some sound sometimes.

It will also ensure that you are not spraying sideways or upwards or spraying water onto the pit. When the pump is running, and you have got water spitting out, and it’s perfectly normal for water to get out of the pump.

However, if any air gets trapped between the check valve and the pump, the weep hole will allow the air to escape with some water. Eventually, your pump will start working, and you will see the water getting out of the discharge pump.

Installation of Weep Hole

The process is very simple. All you need to do is get a drill machine and drill a small weep hole at a 45-degree angle. The diameter should 1/8 to 1/4-inch in diameter. 


I’ve seen people that never heard of a weep hole before. People haven’t drilled it, and they are lucky because once an airlock happens, it can cause a huge problem. Drilling a sump pump weep hole more of a preventive measure, so you should definitely do this in sump and sewage applications.

About the Author Juan Williams

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