1. (a) Summary table purpose. The maximum contaminant levels (MCLs), maximum residual disinfectant levels (MRDLs), treatment techniques, and action levels are presented in this section as a reference source. Only the regulatory concentrations are shown in these tables. Compliance requirements are given in the specific section for each chemical.
2. (b) Maximum contaminant levels for inorganic compounds. The MCLs for inorganic contaminants listed in this subsection apply to public water systems as provided in §290.106 of this title (relating to Inorganic Contaminants).
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3. (c) Maximum contaminant levels (MCLs) for organic compounds. The following maximum contaminant levels for synthetic organic contaminants and volatile organic contaminants apply to public water systems as provided in §290.107 of this title (relating to Organic Contaminants).

   1. (1) The following are the maximum contaminant levels for synthetic organic contaminants.
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   2. (2) The following are the maximum contaminant levels for volatile organic contaminants.
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4. (d) Maximum contaminant levels for radiological contaminants. Maximum contaminant levels for radiological contaminants apply to public water systems as provided in §290.108 of this title (relating to Radiological Sampling and Analytical Requirements). The maximum contaminant levels for beta particle and photon radioactivity from man-made radionuclides in drinking water are as follows.

   1. (1) The maximum contaminant level for combined radium-226 and radium-228 is 5 pCi/l.
   2. (2) The maximum contaminant level for gross alpha particle activity (including radium-226 but excluding radon and uranium) is 15 pCi/l.
   3. (3) The average annual concentration of beta particle and photon radioactivity from man-made radionuclides in drinking water shall not produce an annual dose equivalent to the total body or any internal organ greater than four millirem (mrem)/year.
   4. (4) If two or more radionuclides other than tritium or strontium-90 are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed four mrem/year. Average annual concentrations of tritium or strontium-90 assumed to produce a total body or organ dose of four mrem/year are as follows:
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5. (e) Microbial contaminants. The MCL for microbial or bacteriological contaminants applies to public water systems as provided in §290.109 of this title (relating to Microbial Contaminants). The MCL for microbiological contaminants is based on the presence or absence of total coliform bacteria in a sample.

6. (f) Minimum and MRDLs. Minimum and MRDLs apply to public water systems as provided in §290.110 of this title (relating to Disinfectant Residuals).

   1. (1) The minimum residual disinfectant concentration in the water entering the distribution system is 0.2 mg/L free chlorine or 0.5 mg/L chloramine.
   2. (2) The minimum residual disinfectant concentration in the water within the distribution system is 0.2 mg/L free chlorine or 0.5 mg/L chloramine.
   3. (3) The maximum residual disinfectant level of chlorine dioxide in the water entering the distribution system is 0.8 mg/L.
   4. (4) The maximum residual disinfectant level of free chlorine or chloramine in the water within the distribution system is 4.0 mg/L based on a running annual average.

7. (g) Turbidity. Systems must meet the turbidity treatment technique requirements as provided in §290.111 of this title (relating to Turbidity).

   1. (1) Until January 1, 2002, the turbidity level of the combined filter effluent must never exceed 5.0 NTU and the turbidity level of the combined filter effluent must be 0.5 NTU or less in at least 95% of the samples tested each month.
   2. (2) Effective January 1, 2002 the turbidity level of the combined filter effluent must never exceed 1.0 NTU and the turbidity level of the combined filter effluent must be 0.3 NTU or less in at least 95% of the samples tested each month.
   3. (3) Systems are subject to individual filter turbidity provisions of §290.111 of this title.
8. (h) Disinfection by-product precursors. The treatment technique requirements for disinfection by-product precursors apply to water systems as provided in §290.112 of this title (relating to Total Organic Carbon (TOC)).

9. (i) Disinfection by-products (TTHM and HAA5). The MCLs for TTHM and HAA5 apply to water systems as provided in §290.113 of this title (relating to Disinfection By-products (TTHM and HAA5)). The MCLs for TTHM and HAA5 are:

   1. (1) the MCL for TTHM is 0.080 milligrams/liter; and
   2. (2) the MCL for HAA5 is 0.060 milligrams/liter.

10. (j) Disinfection by-products other than TTHM and HAA5. The maximum contaminant levels for chlorite and bromate apply to water systems as provided in §290.114 of this title (relating to Disinfection By-products Other than TTHM and HAA5). The MCLs for chlorite and bromate are as follows:

    1. (1) the MCL for chlorite is 1.0 mg/L; and
    2. (2) the MCL for bromate is 0.010 mg/L.

11. (k) Lead and copper action levels. The action levels for lead and copper apply to water systems as provided in §290.117 of this title (relating to Regulation of Lead and Copper). Action levels for lead and copper are as follows:

    1. (1) the action level for lead is 0.015 mg/l; and
    2. (2) the action level for copper is 1.3 mg/l.

Source Note:The provisions of this §290.104 adopted to be effective September 13, 2000, 25 TexReg 8880; amended to be effective May 16, 2002, 27 TexReg 4127.