Water Pump Prime Procedure FAQ

Water level in pipe falls during priming
Signs of leaky foot valve or pipe or check valve

Pump Priming Procedure: Water Level Keeps Dropping FAQs

Tip: See PRIME the PUMP, HOW TO

The water level in the pump drops as I'm priming it - does this mean the foot valve leaks?

Hi. I have read the article on losing prime and have been very grateful for all of the information on the site.

I'm new to wells and still would like some more experienced opinions. I have a well with a low flow that pumps into a below-ground 6000 gallon reservoir which is then jet-pumped into my two above ground pressure tanks.

Recently, I have lost prime on it a couple of times. If I leave the system idle for 24 hours don't use any water, when the jet pump kicks in there is a discharge of air and then the water pressure returns. Where is the air coming from? Is something going faulty?

There is a screw cap located on the line between the foot in the reservoir and the check valve before the jet pump where I can fill the intake up with water before priming the pump from the output. When I fill the intake I can see the water level drop a little after 10 minutes.

Does this mean I have a bad foot valve or when the cap screw is replaced should the check valve at the pump prevent the water level drop? Sorry for the long description.
On 2018-12-12 by Bryan

by (mod) - you need to find the leak in piping, at a foot valve or check valve, or at the pump itself

When priming a pump it's normal for water to go down in the pump chamber as water flows out into the well pipe - which also needs to be filled as part of the priming process.

But once you've put enough water into the system to fill both pump and well pipe(s), then if the level keeps dropping, there's a leak somewhere in the pipe, foot valve, or even right at the pump.

So how much water should be enough to prime the pump?

The answer is one we can calculate, as I explain at WATER VOLUME NEEDED to PRIME THE PUMP - how much water will you need?

As you keep losing prime it's probably one of the causes in the article

PUMP PRIME, REPEATED LOSS

The natural place to start is by looking for a bad check valve for leak in the water piping. You could also have a leak in the pump body itself.

Find the leak.

Our well and pump work fine after I found and fixed the leak

Thanks for all of your help. I fixed the small, (very small), leak in the output and the well has now been functioning flawlessly for 4 days. I'm still concerned that the level drops in the pipes when I prime it but it doesn't seem to affect the operation at the moment. I'll leave it until I need to address it. Thanks again.

I was about to say I've checked those places, but I went and checked again and there was a tiny leak in the output pipe. I fixed that by tightening it, snapping the PVC joint and rebuilding that section of pipe

....oh boy. .....

.So now I am waiting to see if there are any more leaks.

There still is, however, a noticeable drop in the water level when I am priming the pump and no conspicuous water leaking out. Does that bring me back to the check and foot valve? How long should these valves hold the water in the pipes?

Minutes/days? Since I am seeing the water drop where I fill the line on the output, does that point to a failing check valve, (much easier to replace)?
Thanks again. On 2018-12-17 by Bryan