There are deep wells (more than 25 feet deep) and shallow wells (25 feet or less). A typical well pump can pull up about 25 feet of water. If the well is deeper than 25 feet, the pump will have to be installed at the bottom of the well to push the water up. Pumps are better at pushing than pulling.
The most powerful pump is a submersible pump that is installed in a deep well, and it won’t always be visible. A single-line jet pump indicates a shallow well. A two-line jet pump indicates a deep well where the pump is visible.
6.2.3 Well Pressure Tanks
A well pressure tank functions to deliver water at a relatively consistent pressure to the dwelling fixtures. A pressure tank can be a simple cylindrical tank filled with air or a tank with a bladder or diaphragm inside. Pressure tanks can be as small as 5 gallons or as large as 80 gallons. These tanks usually sweat condensate; therefore, insulating a tank's lower half is recommended.
There should be a pressure gauge installed at the tank. A pressure switch that operates the pump should be installed. The main water shut-off valve should be nearby. An air valve of some type is usually installed on the tank’s top.
There should be a 20-psi differential minimum between the cut-in and cut-out points. Submersible pumps are typically set at 40 and 60 psi.
6.2.4 Well System Defects
Inadequate water supply is a defect for a well system. Wells can be tested with draw-down, capacity, flow-rate and recovery tests.
Water quality of a private water source should be tested every year for bacteria such as coliform. Contamination of the water supply is a health hazard and a defect. There could be poor surface grading around the well head. The casing could be too short. The cover could be damaged or not watertight.
The pump may not be working properly. If the pump is visible, observe and listen to the pump while it is operating.
Check the pump system with a voltage meter detector before touching it. Inspect all components. The electrical wiring at the pump may be damaged, loose or incorrectly installed. Check for over-fusing. Check for incorrect type of wire or incorrect wire size. Check grounding.
The tank may be rusted, leaking, producing excessive condensate, water-logged, or unstable. www.nachi.org