This article, written by the American Ground Water Trust was originally published in THE AMERICAN WELL OWNER, 2000, Number 2]


Ever been in the shower when suddenly the pressure drops and the shower turns to a drip because someone turned on the kitchen tap or started the washing machine? This can happen if either your water utility pipeline or your private well system doesn’t have enough pressure. Has this been gradually getting worse or has it always been like that? What can you do about it? If you are on pipeline water, first check with your utility. If you are near the end of the line or if the utility has old infrastructure, it may be that you will have to install your own booster pump and pressure tank.

Water flows out of taps because of pressure in the system. For most well systems it is the well pump that provides the pressure that makes water flow from your taps. The overall rate of flow is related to pump capacity. If your pump will only supply 5 gallons per minute then there should be no surprise at a pressure drop if you create a 10-gallon per minute demand. A pressure tank in a water system is designed to store a few gallons so that the pump does not have to switch on for small demands such as a glass of water, but a tank can’t provide sustained flow greater than the pump capacity.

So what can you do?

First check* that the system you do have is working properly. Check that there is adequate pressure in the pressure tank (easy to check and fix). If you are in an area of hard water you may have a build-up of scale that is causing pressure drop because of increased friction in the pipes (relatively easy to check, hard to fix, but easy to prevent).

Install a device* to solve the problem. There are three basic solutions:

ß Install a constant pressure valve between the pump and the pressure tank. This will automatically adjust flow from the well pump to meet a pre-set pressure. You still won’t be able to get water out at a flow rate greater than the pump will deliver. These devices are relatively inexpensive and easy to install.*

ß Add additional pressure tank capacity to meet peak demands for water that are in excess of pump capacity. This can help overcome short-term demands but may not solve the problem of running lawn sprinklers, washing machines and showers simultaneously. Selecting pressure tanks, ensuring that two tanks are compatible to work together efficiently and that the existing pump can cope, will require the services of a well or water systems expert.*

ß Replace* the existing pump with a variable speed pump to maintain constant pressure. Traditional submersible well pump motors run at a constant speed (typically 3,400 rpm) variable speed motors can run up to 8,000 rpm. The speed of the motor is regulated by the home’s demand for water. An electrical/mechanical device measures the demand for pressure and adjusts the pump flow rate to match. Variable speed pump motors may have slow start-up that has added benefits of reducing torque on the pump and piping in the well in addition to eliminating power surges. Variable speed pumps use less electricity and require smaller pressure tanks.

Constant water pressure is not only a convenience for homeowners. Water softeners, iron removal devices and other conditioning equipment work more efficiently under conditions of constant pressure. The private well water supply industry has moved far beyond the era of buckets on a rope. Don’t get left behind. If you have a water system problem relating to yield or quality, there is almost certainly a solution. For more information about water systems you can contact www.watersystemscouncil.org

[*Installing water system equipment is not a recommended arena for amateurs.]

[© American Ground Water Trust. This article may be reprinted for non-commercial educational purposes provided it is used in its entirety and that reference is made to its source as an article in THE AMERICAN WELL OWNER, 2000, Number 2]