Water Well Chlorination

Aqua recommends chlorinating your well as the first step in trying to remedy an unsafe sample, high iron, iron bacteria, hydrogen sulfide & anytime the well is entered for service.

Chlorination Instructions

 Warning: It is recommended a licensed pump installer chlorinate water wells. Do not attempt if the pump or piping is connected to the well cap or if you have a flowing well or pressurized well head. Calcium hypochlorite is a hazardous material and can cause severe injury, it is extremely important to handle with caution & care. Chlorinating wells in most instances, is an effective means of disinfecting a well. Under certain conditions, obstructions, corrosion & pump failure can occur in the well & plumbing system.

Example Calculation

Well Information

Well casing diameter= 6 in
Well depth= 200 ft
Depth to water from surface= 75 ft


Standing water in well=125 ft (200′ – 75′)
125′ x 1.50 gallons= 187.50 gals per Table A
187.5 gals./100= 1.87 x .66 =1.23lbs Table B
187.5 gals./100=1.87 x 3.6 = 6.73qts Table B

1.23 lbs Granular or 6.73 qts Liquid bleach
will be needed to chlorinate your well

Gallons of Water in Your Well

2” diameter:  .17 gals.     Per foot
4” diameter:  .66 gals.    Per foot
6” diameter:  1.50 gals.  Per foot
5” diameter:  1.04 gals.  Per foot
8” diameter:  2.60 gals. Per foot

Amount of chlorine needed for a 500 mg/l solution per 100 gallons of water.

Sodium Hypochlorite Household Bleach
(5% available chlorine)
3.6 quarts
Approx 1 gallon

Calcium Hypochlorite Tablets/Granular
(70% available chlorine)
.66 pounds
Approx 10 ounces