Section 11-20-7.5 - Maximum residual disinfectant levels(a) Maximum residual disinfectant levels (MRDLs) are as follows: Disinfectant residual | MRDL(mg/L) |
Chlorine | 4.0 (as Cl2) |
Chloramines | 4.0 (as Cl2) |
Chlorine dioxide | 0.8 (as ClO2) |
(b) Compliance dates.(1) CWSs and NTNCWSs. Public water systems supplied by either a surface water source or by a ground water source under the direct influence of surface water serving 10,000 or more persons must comply with this section beginning January 1, 2002. Public water systems supplied by either a surface water source or by a ground water source under the direct influence of surface water serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this section beginning January 1, 2004.(2) Transient NCWSs. Public water systems supplied by either a surface water source or by a ground water source under the direct influence of surface water serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. Public water systems supplied by either a surface water source or by a ground water source under the direct influence of surface water serving fewer than 10,000 persons and using chlorine dioxide as a disinfectant or oxidant and systems using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.(c) The director hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum residual disinfectant levels identified in subsection (a): control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels.[Eff and comp 11/30/02; comp 12/16/05; comp 11/28/11; comp MAY 02 2014 ] (Auth: HRS §§ 340E-2, 340E-9) (Imp: HRS §§ 340E-2, 340E-9; 42 U.S.C. §§300 f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, 300j-11; 40 C.F.R. §141.65 )