PDFWAC 246-292-040
Classification of public water systems.
The department shall classify water treatment plants and distribution systems.
(1) Water treatment plants.
(a) Water treatment plants are classified according to the point system in the ABC "Purification Plant Criteria" publication (October 2007) and are in Table 1.
Table 1
Water Treatment Plant Classification
Total Points Assigned | Water Treatment Plant Classification | |
Less than 31 | Class 1 | |
31 to 55 | Class 2 | |
56 to 75 | Class 3 | |
More than 75 | Class 4 | |
(b) The scope of water treatment plant processes include, but are not limited to:
(i) Water filtration;
(ii) Ion exchange;
(iii) Electrodialysis;
(iv) Reverse osmosis; or
(v) Inorganic contaminant removal.
(c) The scope of a water treatment plant does not include unit processes installed for:
(i) In-line fluoridation;
(ii) In-line chlorination; or
(iii) Chemical addition to inhibit corrosion.
(2) Distribution systems are classified according to the population served from a public water system's WFI form and are in Table 2.
Table 2
Distribution Systems Classification
Population Served | Distribution System Classification | |
Less than 251 | Class S | |
251 to 1,500 | Class 1 | |
1,501 to 15,000 | Class 2 | |
15,001 to 50,000 | Class 3 | |
More than 50,000 | Class 4 | |
[Statutory Authority: RCW 70.119.050 and chapter 70.119 RCW. WSR 14-01-003, § 246-292-040, filed 12/4/13, effective 1/4/14. Statutory Authority: Chapter 70.119 RCW and Safe Drinking Water Act, Public Law 104-182; 64 F.R. 5916 - 5921. WSR 01-02-070, § 246-292-040, filed 12/29/00, effective 1/29/01. Statutory Authority: Chapter 70.119 RCW. WSR 94-04-004, § 246-292-040, filed 1/20/94, effective 2/20/94. Statutory Authority: RCW 43.70.040. WSR 91-02-049 (Order 121), recodified as § 246-292-040, filed 12/27/90, effective 1/31/91. Statutory Authority: RCW 70.119.050. WSR 78-10-053 (Order 1343), § 248-55-050, filed 9/22/78.]