Water Well Maintenance and Rehabilitation

submersible-pump

Water wells require regular maintenance to ensure adequate water flow and optimum water quality.

Water Well Maintenance and Rehabilitation

As a water well ages, the rate at which water may be pumped (commonly referred to as the wells yield, flow, or performance) tends to decrease, especially in wells that were not properly developed when first drilled. This fact sheet briefly describes common well problems and discusses prevention and rehabilitation measures.

Water Well Maintenance

Water wells require regular maintenance to ensure adequate water flow and continued drinking water safety. To ensure water quality, well water should be tested annually for total coliform bacteria and E. coli bacteria by a state-accredited testing laboratory.

Water wells should also be inspected annually for obvious signs of damage or contamination. Be sure the area within 100 feet around the well is clear of debris or items that might pollute the water supply.

Water well completion report or log (if you have it) which should include information such as water well depth, date drilled, construction (including casing specifications, grouting, and screen), and water well yield or flow rate in gallons per minute (GPM)

Water quality test reports

Past inspection report

Every three years, additional testing is recommended for pH and total dissolved solids as well as tests related to land uses occurring or expected to occur within sight of the well. Additionally, if there are obvious stains, tastes, or odors in the water, seek testing that will help identify the source of these symptoms.

Well Performance

As a water well ages, the rate at which water may be pumped (commonly referred to as the wells yield, flow, or performance) tends to decrease, especially in wells that were not properly developed when first drilled. A drop or complete loss of water production from a well can sometimes occur even in relatively new wells due to a lowered water level from persistent drought or over-pumping of the well which can dewater the water-bearing zones. More often, reduced well yield over time can be related to changes in the water well itself including:

– Incrustation from mineral deposits

– Bio-fouling by the growth of microorganisms

– Physical plugging of “aquifer” (the saturated layer of sand, gravel, or rock through which water is transmitted) by sediment

– Sand pumping

– Well screen or casing corrosion

– Pump damage

Water Well Rehabilitation

Measures taken to correct these problems are referred to as well rehabilitation or restoration. A successful well rehabilitation will maximize the flow of water from the well. The chances for successful rehabilitation are dependent on the cause(s) of poor wells performance and the degree to which the problem has progressed.

Upon noticing a loss of performance in your well have a professional water well contractor inspect your well, preferably with a downhole camera

To detect deterioration of well performance, you must have a point of reference. Often this reference is the original well construction and pumps test data which are normally supplied to you by the wells driller on the wells completion report or well log when the well is installed. However, even if you do not have this information, significant changes in your well are also a warning sign. Major changes in any of the following well characteristics are an indication that your well or pump needs attention:

Decreased pumping rate

Decreased water level

Decreased specific capacity

Increased sand or sediment content in the water (cloudiness)

Decreased total well depth

The two most common methods to rehabilitate water well are:

chemicals to dissolve the incrusting materials from the well

physically cleaning the well

Physical methods include using a brush attached to a drilling rig, high pressure jetting, hydrofracturing, and well surging.

The latter three techniques all include injecting water (and sometimes chemicals) into the well under extreme pressure. Sometimes contractors will use a combination of these methods depending upon the reason(s) for the decrease in well performance.

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