Shallow wells are usually dug, are often low in dissolved minerals, and often produce good quality water if protected from biological hazards.
Shallow wells can be influenced by nearby surface water and are more likely to contain biological hazards than deep wells.
General Construction Tips for Wells
Make sure that the area between the well casing and the ground is sealed.
To make a surface seal for a well:
- Make well hole a third to a half metre (1–2 feet) larger than well casing.
- Place dried clay or bentonite (a highly absorbent clay) alongside casing.
The clay absorbs water and expands to act as a seal that prevents surface runoff and pathogens from entering through the outside of the well.
Well caps should have a tight-fitting seal to prevent contaminants from entering the well.
On large-diameter dug wells it may be necessary to construct a lid. It should be fitted with a rubber seal to prevent contamination by rodents, insects, or surface water.
If a vent cap is necessary, it should be fitted with a fine-mesh screen.
An important part of construction is the well or pump house. The pump house should be vented to allow the escape of gases that may come from the well, and the vents should be screened against rodents and insects.
Pump houses with unsealed doors and windows make wonderful winter homes for rodents whose droppings can be the source of disease.
The pump or well house should not be used for storage of paint, gardening chemicals, oil or other possible pollutants. These substances can be very harmful even in small quantities if they enter your well.
The well casing should extend a third to a half metre (1–2 feet) above the ground to prevent any chance of floodwater overflowing the top or running down the outside of the well.