Illinois Administrative Code › Title 77 - PUBLIC HEALTH › Part 920 - WATER WELL CONSTRUCTION CODE › Section 920.100 - Finishing and Testing

Current through Register Vol. 48, No. 28, July 12, 2024
a) Upper
			 Terminal. The casing or riser pipe shall be terminated at a height above
			 finished ground surface consistent with proposed plans for a pump house and
			 pump installation but not less than 8 inches above finished ground surface or
			 24 inches above maximum high water level where flooding occurs. The well shall
			 be capped watertight until pump installation is made.
b) Disinfection. Only after the well has been
			 effectively cleaned of all remaining drilling mud and drill cuttings can the
			 well be disinfected. The well contractor shall be responsible for properly
			 disinfecting the well upon completion. Disinfection shall also be done after
			 the pump installation is completed. Sufficient chlorine shall be introduced to
			 give a dosage of 100 parts per million to the water in the well.
1) Drilled Wells. The disinfection of drilled
			 wells shall be accomplished in accordance with the following:
DIAM. WELL
GALLONS
AMOUNT OF DISINFECTANT REQUIRED FOR
1 cup = 8 oz. measuring cup
(2) cups = 1pt.; 4 cups = 1 qt.)
1 oz. = 1 heaping tablespoon granules
(16 oz. = 1 lb.)
A)
			 Determine the amount of water in the well by multiplying the gallons per foot
			 by the number of feet of water in the well.
B) For each 100 gallons of water in the well,
			 use the amount of chlorine liquid or compound given in the above tables. Mix
			 this total amount in about 10 gallons of water. If dry granules or tablets are
			 used, they may be added directly to drilled wells.
C) Pour this solution into the top of the
			 well before the seal is installed.
D) Connect one or more hoses from faucets on
			 the discharge side of the pressure tank to the top of the well casing and start
			 the pump, recirculating the water back into the well for at least 15 minutes.
			 Then open each faucet in the system until a chlorine smell appears. Close all
			 faucets. Seal the top of the well.
E) Let stand for several hours, preferably
			 overnight.
F) After standing,
			 operate the pump, discharging water from all outlets until all chlorine odor
			 disappears. Faucets on fixtures discharging to septic tank systems should be
			 throttled to a low flow to avoid overloading the disposal system.
2) Dug/Bored Wells. The
			 disinfection of dug/bored wells shall be accomplished in accordance with the
			 following:
Diameter of well
(in feet)
3
4
5
6
7
8
10
Amount of 5.25 %
laundry bleach to
use per foot of
water (in cups)
1 1/2
3
4 1/2
6
9
12
18
Amount of 70%
Hypochlorite
granules to use
per foot of water
(in ounces)
1
2
3
4
6
8
12
A) The amount of
			 disinfectant required is determined primarily by the amount of water in the
			 well. The table above shows the amount of the chlorine to use for each foot of
			 water in the well, according to its diameter.
B) To determine the exact amount of bleach to
			 use, multiply the amount of disinfectant indicated as determined by the well's
			 diameter times the number of feet of water.
C) This total amount of bleach shall be added
			 to approximately 10 gallons of water, and splashed around the lining, or wall
			 of the well. Be certain that the solution has contacted all parts of the well,
			 using the entire amount of disinfectant. Seal the top of the well.
D) When this is done, pump enough water so
			 the strong chlorine odor is evident. When the odor is detected, stop the
			 pumping and allow the solution to remain in the well overnight.
E) After standing, operate the pump,
			 discharging water from all outlets until all chlorine odor disappears. Faucets
			 on fixtures discharging to septic tank systems shall be throttled to a low flow
			 to avoid overloading the disposal system.
3) Water Samples. Upon completion of a new
			 well or modification of an existing well, the contractor shall give the owner
			 information prepared by the Department explaining the importance of water well
			 sampling, procedures for sampling, and how the water can be tested to assure a
			 safe supply of water.