What is a Well Flow Test?

Simply put, a well flow test is a test that measures the usable amount of water that a well can deliver to a house or a building. The test calculates the amount of water that can be pumped from the well through a well water system into a home or building. Several factors will affect the volume of water: capacity of the well pump, the diameter of the pipes, and obstructions along the way.

How is the test done?

A well flow test is conducted by connecting a measuring device to an outside spigot and measuring the flow of water over a defined period of time. As a well pump cycles on and off the flow will increase and decrease. These variations are measured and documented.

What do the results tell you?

The well flow test will give you an expectation of what kind of water volume and flow you can expect in the house. Should you expect to be able to take a shower while someone else is doing the dishes in the kitchen?

If the water flow stops during the test
If the flow of water stops during the test, there are several possible reasons. The well pump may have failed (which is very unusual). The column of water in the well may be depleted (the well “ran dry”). The breaker powering the well pump may have tripped.

If there are wide variations between the higher and lower flow rates
Wide variations in the flow rate during the test can be an indication of an issue with the way the well system is operating or configured. The well pressure tank may be faulty and not regulating water pressure properly. The well pressure switch (that turns the well pump on an off) may not be set properly or may not be working properly.

If the flow rate at the end is significantly lower than the flow in the beginning
If the high and low readings are both much lower at the end of the test than at the beginning, this may be an indication that the water sources supplying the well may be constrained. Put differently, the test used the water in the well faster than nature could replenish it. If this is the case, there are things that can be done to safeguard you against running out of water.

What do the results DO NOT tell you?

Droughts and dry seasons
The well flow test will not predict how well your well will make it through a drought. Should an upcoming summer be unusually dry and the water sources and aquifers that feed your well dry up, your well may be at risk. A well flow test is done at a point in time and can only report on the conditions at the time that the test was performed.

Pressure
A well flow test does not tell you very much about the water pressure in the house. Relatively similar flow readings can be measured with a pressure of 40 pounds per square inch (“PSI”) or 55 PSI. The difference between low water pressure in a house and high water pressure can be seen in how much water you might get from a third floor shower. Water pressure drops by 1 PSI with every 2.31 feet in rise. Low water pressure in a house can usually be addressed somewhat easily.

How is a well flow test different from a well recovery test?

A well flow test measures the amount of water that is available in the house for use over a period of time. The measure might be an average of 5 gallons per minute. 5 gallons per minute would suggest that there is plenty of supply for most households.

A well recovery test measures how quickly the water sources supplying a well will fill the well. During a well recovery test, the column of water in the well is drained down a measured amount and the time it takes for column to recover is measured. This test is useful to determine how quickly the column of water in the well recovers after being drawn down, but it does little to test you about whether you have a consistent and sufficient water supply in the house. A well recovery test result of 1 gallon per minute may be fine, if the column of water in the well is 600 feet deep. This number does not tell you anything about the number of gallons per minute of water you will have in the house.

Next steps

Ask about adding a well flow test to your inspection, or schedule one as a standalone service!