Section 370. Water quality and quantity

A. Class IV wells exempt. The water quality requirements contained in this section apply only to Class III private wells. Class IV private wells (wells not constructed as a source of drinking water) are not subject to any quality requirements. These regulations contain no well yield requirements. See 12VAC5-630-460 for suggested minimum well yields for residential supplies.

B. Sample tap. A sample tap shall be provided at or near the water entry point into the system so that samples may be taken directly from the source; this requirement may be met by utilizing the first tap on a line near where the plumbing enters the house (may be a hose bib), provided the tap precedes any water treatment devices.

C. Disinfection. The entire water system including the well shall be disinfected prior to use (12VAC5-630-430 and 12VAC5-630-470).

D. Sampling. After operating the well to remove any remaining disinfectant, a sample of the water from the well shall be collected for bacteriological examination. The sample may be collected by the owner, well driller, or other person in accordance with procedures established by the department and provided the sample is submitted to a private laboratory certified by the Department of General Services, Division of Consolidated Laboratory Services, for analysis.

E. Test interpretation. A Class III private well shall be considered satisfactory if the water sample(s) test(s) negative for coliform organisms as described in subdivision 1 or 2 below. Sources with positive counts shall be tested as described in subdivision 3 below to determine if the water supply is amenable to continuous disinfection (chlorination). Samples that exhibit confluent growth shall be considered inconclusive and another sample shall be collected.

1. Where a private well has no unsatisfactory water sample within the previous 12 months, one water sample which tests negative for coliform bacteria shall be considered satisfactory for coliform organisms.

2. Where a private well has had one or more positive water samples within the past 12 months for coliform bacteria, at least two consecutive samples must be collected and found negative for coliform organisms before the supply may be considered satisfactory for coliform organisms. The samples must collected at least 24 hours apart and the well may not be disinfected between samples.

3. When a private well does not test satisfactory for coliform organisms continuous disinfection may be recommended to the homeowner if the water supply is found to be suitable for continuous disinfection. A minimum of 10 samples shall be collected and tested for total coliform using an MPN methodology. The geometric mean of the samples shall be calculated and if the result is less than 100 organisms per 100 ml, the supply shall be considered satisfactory for continuous disinfection.

F. Water treatment. If tests indicate that the water is unsatisfactory and no other approvable source is available, adequate methods of water treatment shall be applied and demonstrated to be effective pursuant to 12VAC5-630-370 E 3 prior to the issuance of an inspection statement. The district or local health department shall be consulted when treatment is necessary.

Historical Notes

Derived from VR355-34-100 § 3.3, eff. April 1, 1992.

Statutory Authority

§§ 32.1-12 and 32.1-176 of the Code of Virginia.