Section 809.11. Inorganic chemical maximum contaminant levels and BATs.

 

(1)   Applicability. The following requirements apply to all of the maximum contaminant levels for inorganic contaminants:

(a) The maximum contaminant levels for nitrate and nitrite apply to both community water systems and non-community water systems, except as provided in sub. (3) .

(b) The maximum contaminant level for fluoride only applies to community water systems.

(c) The maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, mercury, nickel, selenium and thallium apply to community water systems and non-transient, non-community water systems.

(d) Compliance with maximum contaminant levels for inorganic chemicals is calculated under s. NR 809.117 .

(2)   MCLs for inorganics. The following are the maximum contaminant levels for inorganic contaminants: - See PDF for table

Antimony   0.006

Arsenic   0.010

Asbestos   7 Million fibers/Liter
  (longer than 10 um)

Barium   2

Beryllium   0.004

Cadmium   0.005

Chromium   0.1

Cyanide(as free Cyanide)0.2

Fluoride   4.0

Mercury   0.002

Nickel   0.1

Nitrate   10 (as Nitrogen)

Nitrite   1 (as Nitrogen)

Total Nitrate Nitrite   10 (as Nitrogen)

Selenium   0.05

Thallium   0.002

(3)   Operation with nitrates not exceeding 20 mg/l. At the discretion of the department, nitrate as nitrogen levels not to exceed 20 mg/l may be allowed in a non-community water system if the water supplier demonstrates all of the following to the satisfaction of the department:

(a) The water will not be available to children under 6 months of age or any female who is or may become pregnant.

(b) The water supplier meets the public notification requirements under s. NR 809.958 , including continuous posting of the fact that nitrate as nitrogen levels exceed 10 mg/l and the potential health effects of exposure.

(c) Local and state public health authorities will be notified annually of nitrate as nitrogen levels that exceed 10 mg/l.

(d) A supply of bacteriologically safe drinking water, containing less than 10 mg/l nitrate as nitrogen, is provided for infants less than 6 months of age and any female who is or may become pregnant.

(e) No adverse health effects will result.

(4)   Best available treatment . The best available treatment technologies for inorganic contaminants are as follows:

(a) The best available technologies or BATs for achieving compliance with the maximum contaminant levels for the inorganic contaminants listed in sub. (2) , except for fluoride, are as follows: - See PDF for table

Key to BATs in Table:

1 = Activated Alumina

2 = Coagulation/Filtration (not BAT for public water systems < 500 service connections)

3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon

5 = Ion Exchange

6 = Lime Softening (not BAT for public water systems < 500 service connections)

7 = Reverse Osmosis

8 = Corrosion Control

9 = Electrodialysis

10 = Oxidation (Chlorine)

11 = Ultraviolet

12 = Oxidation/Filtration

13 = Alkaline Chlorination (pH ≥ 8.5)

(b) A water supplier may use an alternative treatment not listed in par. (a) if it is demonstrated to the department, using pilot studies or other means, that the alternative treatment is sufficient to achieve compliance with the MCLs in sub. (2) .

(5)   Small water system compliance technologies for Arsenic.

(a) The EPA identifies the following table as the affordable technology, treatment technique, or other means available to public water systems serving 10,000 persons or fewer for achieving compliance with the maximum contaminant level for arsenic: - See PDF for table

(b) The department may allow Point of Use (POU) treatment only if the department determines that treatment prior to entry to the distribution system is not feasible.

CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10; CR 15-049 : am. (2), (3) (a), (d), (4) (a) Register March 2016 No. 723 , eff. 4-1-16.