SECTION 252:631-3-10. Process control tests

  Control tests must be performed in accordance with procedures approved by the DEQ.

(1)   Surface water, groundwater under the direct influence of surface water, and springs.

(A)   Systems that use coagulation, settling, softening or filtration must do the following chemical control tests on the filtered water twice a day, record the results on a report form provided or approved by the DEQ, and submit the form to the DEQ Water Quality Division each month, with a copy to the local DEQ representative:

(i)   Alkalinity - Phenolphthalein (P);

(ii)   Alkalinity - Total;

(iii)   Hardness (where softening is used);

(iv)   pH value; and

(v)   Stability to calcium carbonate (once per day);

(B)   Perform jar tests as needed to determine the optimum coagulant dosages for plant control and operation to meet turbidity requirements.

(C)   Turbidity and residual disinfection samples must be collected and analyzed in accordance with 40 CFR Part 141, Subparts H, P, T and W.

(D)   Systems that use membrane filtration shall perform direct integrity testing and indirect integrity monitoring in accordance with 40 CFR Part 141.719(b)(3) and (4).

(2)   Groundwater supplies. The following tests are required for public water supply systems utilizing groundwater as a source. Test results must be listed as indicated on the appropriate forms and submitted to DEQ:

(A)   For all public water supply systems that practice chlorination, the chlorine residual shall be tested and recorded once daily at the POE;

(B)   For community and NTNC public water supply systems:

(i)   Static level and pumping level of each well must be determined quarterly;

(ii)   Alkalinity, pH, and stability must be determined at least monthly for community systems and at least quarterly for non-transient non-community water systems;

(iii)   Where ion-exchange softening is provided, determine the hardness of the finished water once a day; and

(iv)   Where nanofiltration, reverse osmosis or electrodialysis is provided, perform the following chemical control tests on the treated water once a day:

(I)   Alkalinity - Phenolphthalein (P),

(II)   Alkalinity - Total,

(III)   Hardness,

(IV)   pH value, and

(V)   Stability to calcium carbonate.

(3)   Purchase water systems. Purchase water systems that are required to maintain a disinfection residual shall monitor the disinfectant residual in the distribution system as follows:

(A)   Those serving a population of 1,500 or less shall monitor the disinfectant residual at representative locations in the distribution system at least once every seven days;

(B)   Those serving a population of 1,501 to 20,000 shall monitor the disinfectant residual at representative locations in the distribution system at least three times a week on non-consecutive days; or

(C)   Those serving a population of greater than 20,000 shall monitor the disinfectant residual at representative locations in the distribution system at least five times a week.

(4)   Special tests.

(A)   Systems that remove iron or manganese must test the raw and finished water weekly for those metals.

(B)   Systems that treat or blend for the reduction in concentration of regulated contaminants must monitor the raw and finished water for those contaminants daily in addition to collecting compliance samples.

(C)   Threshold odor and other tests may be required by the DEQ based on local conditions.

(D)   Systems that treat or blend for the reduction in concentration of nitrates must test the raw and finished water at least once a day for nitrates.

(E)   Systems that apply phosphate chemicals in the treatment process must test the finished water at least once a day for phosphates.

(5)   Fluoridation. Where fluoridation is practiced, the system must:

(A)   analyze the water twice a day for fluoride content, both before and after fluoridation;

(B)   forward a copy of the analytical report (ODH form No. 561/DEQ form No. 631-001) to the DEQ monthly and keep a copy at the plant (ODH also requires a copy); and

(C)   submit a sample of treated water to the DEQ State Environmental Laboratory, or to a DEQ-accredited laboratory, for analysis of fluoride content every month.

(6)   Sampling disinfectants in distribution system. The following control tests shall be performed in the distribution system for all systems that disinfect. Sampling points shall be changed regularly so the system is sampled completely at least once each week or in accordance with a sampling plan approved by DEQ.

(A)   Chlorine. Systems that use chlorine shall test for free chlorine and total chlorine residual twice a day in the distribution system.

(B)   Chloramines. Systems that use chloramines shall test for total chlorine residual twice a day in the distribution system. See 252:631-3-3(d) for the requirements for Heterotrophic Plate Counts.

(C)   Other disinfectants. Systems that use ozone or chlorine dioxide shall perform process control tests in accordance with 40 CFR Section 141.132.

[Source: Added at 17 Ok Reg 1987, eff 6-12-00; Amended at 20 Ok Reg 61, eff 10-31-02 (emergency); Amended at 20 Ok Reg 1153, eff 6-1-03; Amended at 25 Ok Reg 2305, eff 7-11-08; Amended at 31 Ok Reg 1311, eff 9-12-14; Amended at 32 Ok Reg 986, eff 9-15-15; Amended at 33 Ok Reg 1490, eff 9-15-16; Amended at 35 Ok Reg 1330, eff 9-15-18]