Hawaii Administrative Rules
Title 11 - DEPARTMENT OF HEALTH
Subtitle 1 - GENERAL DEPARTMENTAL PROVISIONS
Chapter 20 - RULES RELATING TO PUBLIC WATER SYSTEMS
Section 11-20-7.5 - Maximum residual disinfectant levels
Universal Citation: HI Admin Rules 11-20-7.5
Current through February, 2024
(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.
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