(1) The proposed water well shall be located where it is not subject to ponding and is not in the floodway, except as provided in chapter 86.16 RCW.

(2) It shall be protected from a one hundred-year flood and from any surface or subsurface drainage capable of impairing the quality of the groundwater supply.

(3) All wells shall not be located within certain minimum distances of known or potential sources of contamination.

(a) Some examples of sources or potential sources of contamination include:

(i) Septic systems, including proposed and reserve sites under a valid septic design: Provided, that the design has been approved for installation by a health authority;

(ii) Manure, sewage, and industrial lagoons;

(iii) Landfills;

(iv) Hazardous waste sites;

(v) Sea/salt water intrusion areas;

(vi) Chemical and petroleum storage areas;

(vii) Pipelines used to convey materials with contamination potential;

(viii) Livestock barns and livestock feed lots.

(b) Minimum set-back distances for water wells other than for public water supply are:

(i) Five feet from any existing building structure or building projection. Water wells shall not be located in garages, barns, storage buildings or dwellings. When locating a nonpublic water well adjacent to a building, the well location shall be measured from the building sewer and closest building projection.

(ii) Fifty feet from a septic tank, septic holding tank, septic containment vessel, septic pump chamber, and septic distribution box.

(iii) Fifty feet from building sewers, public sewers, collection and nonperforated sewer distribution lines except building drains.

(iv) One hundred feet from the edge of a drainfield, proposed drainfield which has been approved by a health authority, and reserve drainfield areas.

(v) One hundred feet from all other sources or potential sources of contamination except for solid waste landfills.

(vi) One thousand feet from the boundary of a permitted or previously permitted (under chapter 173-304, 173-306, 173-351, or 173-350 WAC) solid waste landfill as defined by the permit; or one thousand feet from the property boundary of other solid waste landfills. Except, a variance may be granted if documentation is provided that demonstrates the construction and operation of the well adjacent to the landfill will not further degrade the environment and will not cause a public health risk.

(c) All public water supply well locations shall be approved by the department of health or the local health jurisdiction or other department of health designee.

(i) Before construction begins, final site approval must be obtained from the department of health or the local health jurisdiction.

(ii) The requirements of the state board of health regulation regarding public water supplies shall apply.

(iii) This regulation includes requirements for zones of protection, location of the well, accessibility features, and certain construction requirements.

(4) In siting a well, the driller shall consider:

(a) All local and state water well construction regulations, policies, and ordinances;

(b) Permeability of the soil or rock;

(c) Adjacent land uses;

(d) Local groundwater conditions; and

(e) End use of the well.

(5) Before construction, the water well operator should strongly emphasize to the well owner, the importance of retaining good accessibility to the well to permit future inspection, maintenance, supplementary construction, and decommissioning.