New Hampshire Code of Administrative Rules
Env - Department of Environmental Services
Subtitle Env-Ws - Division of Water
Chapter Env-Ws 300 - NEW HAMPSHIRE DRINKING WATER RULES
Part Env-Ws 382 - DISINFECTANT/DISINFECTION BYPRODUCTS RULE
Section Env-Ws 382.06 - Analytical Requirements
Current through Register No. 13, March 27, 2025
(a) A water system shall use the analytical methods specified in Env-C 303.04.
(b) The following documents are incorporated by reference:
(c) Disinfection byproducts shall be measured by the following methods:
Table 382-1
APPROVED METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING
Methodology(2) | EPA Method | Standard Method | Byproduct Measured(1) | |||
TTHM | HAA5 | Chlorite(4) | Bromate | |||
P&T/GC/EICD & PID | 502.2(3) | X | ||||
P&T/GC/MS | 524.2 | X | ||||
LLE/GC/ECD | 551.1 | X | ||||
LLE/GC/ECD | 6251 B | X | ||||
SPE/GC/ECD | 552.1 | X | ||||
LLE/GC/ECD | 552.2 | X | ||||
Amperometric Titration | 4500-CIO2E | X | ||||
IC | 300.0 | X | ||||
IC | 300.1 | X | X |
(d) The following notes shall apply to Table 382-1:
(e) Analysis for disinfection byproducts shall be conducted by a laboratory that has received accreditation by the department.
(f) To receive accreditation by the department, a laboratory shall perform analyses of performance evaluation samples as specified in Env-C 306.
(g) Chlorite samples collected daily at the entrance to the distribution system pursuant to Env-Ws 382.10 shall be measured by, or under the supervision of, an operator certified under Env-Ws 367.
(h) Residual disinfectant concentrations for free chlorine, combined chlorines, also known as chloramines, and chlorine dioxide shall be measured:
Table 382-2
APPROVED METHODS FOR DISINFECTANT RESIDUAL COMPLIANCE MONITORING
Methodology | Standard method | ASTM method | Residual Measured 1 | |||
Free Chlorine | Combined Chlorine | Total Chlorine | Chlorine Dioxide | |||
Amperometric Titration | 4500-Cl D | D 1253-86 | X | X | X | |
Low Level Amperometric Titration | 4500-Cl E | X | ||||
DPD Ferrous Titrimetric | 4500-Cl F | X | X | X | ||
DPD Colorimetric | 4500-Cl G | X | X | X | ||
Syringaldazine (FACTS) | 4500-Cl H | X | ||||
Iodometric Electrode | 4500-Cl I | X | ||||
DPD | 4500-ClO2 D | X | ||||
Amperometric Method II | 4500-ClO2 E | X |
(i) A certified operator shall monitor the following:
(j) DOC shall be measured by one of the methods specified in (i)(3), above.
(k) Prior to analysis, DOC samples shall be filtered through a 0.45 µm pore-diameter filter. Water passed through the filter prior to filtration of the sample shall serve as the filtered blank.
(l) The filtered blank shall be analyzed for DOC using one of the methods specified in (i) above, and shall be identical to the method used in the analysis prior to filtration.
(m) The DOC in the filter blank shall be less than 0.5 mg/L.
(n) Acid may be added to the filter blank in accordance with the following:
(o) DOC samples not acidified shall be analyzed as soon as practical after sampling, but shall not exceed 48 hours from the time the sample was collected.
(p) UV absorption shall be measured at:
(q) TOC samples shall not be filtered prior to analysis.
(r) TOC samples shall be acidified to achieve a pH of less than 2.0 by the minimal addition of phosphoric or sulfuric acid as soon as practical after sampling, but no later than 24 hours after sample collection.
(s) Acidified TOC samples shall be analyzed within 28 days.
(t) TOC samples not acidified shall be analyzed as soon as practical after collection but no later than 24 hours after sample collection.
(u) pH shall be measured by the methods set forth in 40 CFR 141.23(k)(1).
(See third Revision Note at chapter heading Env-Ws 300); #7735, eff 8-2-02