Sump Pump Running with No Rain

Last Updated on by Anthony Brown

If your sump pump is running and there is no rain in the sky there is a chance that something is wrong but it also might be working correctly. There are a number of reasons why your pump pick turn on when while it is not raining. Keep reading to learn the 6 reasons why from our expert plumbing team.6

6 Most Common Reasons

Hearing your sump pump turn on when the sun is in the sky can be a cause for concern. Here are a few of the most common reasons why your pump might turn on while the weather is nice and there has been no rainfall.

1. Increase in Ground Water

The most common reason for your sump pumps keeps running while it is not raining is an increase in ground water. Ground water can come from many sources like nearby rivers or lakes, a broken pipe or nearby construction. This water is almost impossible to detect above ground but it can pool at the lowest point in your home causing the pump to run nonstop.

2. Snow is Melting

Another common cause is melting snow. If it recently snowed in your area and the temperature rose above freezing all the snow will start melting, turn into water and seep into the ground. Some of it will be absorbed by plants and the soil but if there was recently a blizzard you should expect to hear your pump running.

3. Rise in Water Table

Water tables change from time to time due to a number of reasons. Some are man made like new construction and others are more natural like increased rainfall or a river changing course. Most of the time the water table will drop back to its normal level but the rise can be permeant if the water has nowhere else to go.

4. Broken Float Switch

Sometimes your pump will keep running due to a broken float switch. If your float switch gets stuck in the “up” position and does not rise and fall with the water levels your pump will not know when to turn off. In some cases this can be fixed by manually adjusting the switch or a can of WD-40. If the switch will not go down into the “off” position you might need a new valve or pump.

5. Pump Not Draining

If your pump keeps running while it is not raining it might be a good idea to check that it is draining water from the pit. There are a number of mechanical and electrical reasons why your pump might continue to run without pumping water from the pit. 

Start by using adding some water to the pit to raise the float switch into the on position. If the pump starts running but the water is not going down the problem is with your pump!

6. Clogged Drain Line

Clogged drain lines mean that even the most powerful pump won’t be able to drain the water in your basin. If your pump seems to be working it might be time to clear the drain lines. 

Over time dirt, debris and other small particles that pass through your pump end up stuck in the drains. Once water is unable to drain water will start to build up in the basin and cause the pump to overheat, malfunction and in some cases start steaming or smoking.

Frequently Asked Questions

How often should sump pump run when raining?
Most sump pumps run every 15 to 20 seconds while it is raining. If you have a weaker pump or it is raining harder than normal it may run more often.

Why does my sump pump run when it rains?
Your sump pump is running while it is raining because water is filling your basin and raising the float switch which causes the pump to turn on.

Should my pump be running constantly after heavy rain?
Yes, after a heavy rain storm the water table under your home will rise which causes your pump to start running.