(a) Each person who repairs, modifies, works on, or otherwise affects the physical components of a well shall clean and disinfect the pump, electrical wiring and controls, drop pipe, and all other equipment each and every time the pump, electrical wiring and controls, drop pipe, and other equipment is placed into the well. In addition, each person (or crew) who performs the above tasks shall maintain at all times on every well site, adequate chlorine compounds to disinfect the well in accordance with the table found in Appendix A.
(b) The well driller shall: - (i) Clean all casing, tools, drilling equipment, and materials prior to beginning the drilling and construction of every well.
- (ii) Clean all pumping equipment and well construction materials (including sand or gravel used in an artificial filter-packed well) before placing them in the well or borehole.
- (iii) Ensure that only potable water is used for drilling and for mixing of sealing material.
(c) The pump installer shall: - (i) Clean all pumping, wiring, and other equipment prior to placement in the well.
- (ii) Clean all materials that may come in contact with down-hole equipment.
(d) All wells used for drinking or sanitary use shall be disinfected after construction, reconditioning, or repair (e.g., submersible pump replacement) and before the well is placed into, or returned to, service. - (i) Following drilling:
- (A) If calcium hypochlorite is used, it shall be slowly poured down the casing and at least 30 minutes shall pass to allow the tablets to fall through the water and dissolve.
- (B) If sodium hypochlorite is used, the solution must reach all parts of the well. To accomplish this, a tube shall be suspended through the well casing so that it reaches the bottom of the well. After it reaches the well bottom, it shall be withdrawn as the sodium hypochlorite solution is pumped through the tube.
- (C) After the chlorine has been applied, the well shall be surged at least three times to improve the mixing and induce contact of the chlorinated water with the adjacent aquifer.
- (ii) Following pump installation:
- (A) Chlorine shall be introduced so that an average chlorine residual of 100 mg/1 is in the entire volume of water in the casing and all parts of the plumbing system (pump, drop-pipe, wiring, pitless assembly, etc.) for a minimum contact period of not less than two (2) hours (overnight is preferable) before flushing and ridding the chlorine solution from the well.
- (iii) See Appendix A for mixing proportions. Chlorine compounds intended for home laundry use, pool, or fountain use should not be used if they contain additives such as antifungal agents, scents, etc.