Md. Code Regs. 26.04.01.15-2

Current through Register Vol. 51, No. 24, December 2, 2024

Section 26.04.01.15-2 - Disinfection Byproducts Sampling and Analytical Requirements

A. Applicability.

(1) Community and Nontransient Noncommunity Water System Stage 1 Disinfection Byproducts Rule (DBPR) Compliance Dates.

(a) Subpart H systems serving 10,000 or more individuals shall comply with Regulation .07F(1)-(4) of this chapter beginning January 1, 2002.

(b) Subpart H systems serving fewer than 10,000 individuals and ground water systems not under the influence of surface water shall comply with Regulation .07F(1)-(4) of this chapter beginning January 1, 2004.

(2) Transient Noncommunity Water System Stage 1 DBPR Compliance Dates.

(a) Subpart H systems serving 10,000 or more individuals and using chlorine dioxide as a disinfectant or oxidant shall comply with the chlorine dioxide MRDL established in Regulation .23D of this chapter beginning January 1, 2002.

(b) Subpart H systems serving fewer than 10,000 individuals 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 shall comply with the chlorine dioxide MRDL beginning January 1, 2004.

(3) Stage 2 DBPR Compliance Dates. Systems shall comply with the requirements specified in §I of this regulation and 40 CFR § 141.620 (Subpart V-Stage 2 Disinfection Byproduct).

B. Monitoring Frequency.

(1) Systems shall take all samples during normal operating conditions.

(2) Systems may consider multiple wells drawing water from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required.

(3) Disinfection Byproduct Precursor. In order to qualify for reduced monitoring for TTHM and HAA5, Subpart H systems not monitoring under the provisions of 40 CFR § 141.132(d) shall take monthly total organic carbon (TOC) samples every 30 days at a location prior to any treatment, beginning April 1, 2008, or earlier if specified by the State. In addition to meeting other criteria for reduced monitoring in 40 CFR § 141.132(b)(1), the source water TOC running annual average shall be less than or equal to 4.0 mg/L (based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5.

(4) Subpart H Systems Serving 10,000 or More Individuals.

(a) Routine Monitoring. Systems shall collect and analyze at least four water samples per quarter per treatment plant during normal operating conditions.

(b) Reduced Monitoring. Systems shall collect and analyze one sample per quarter per treatment plant during normal operating conditions after completing 1 year of monitoring and if the following conditions are met:

(i) The TTHM annual average is less than or equal to 0.040 milligram per liter and HAA5 annual average is less than or equal to 0.03 milligram per liter; and

(ii) The requirements of §B(3) of this regulation are satisfied.

(5) Subpart H System Serving 500 to 9,999 Individuals or Ground Water System, Not GWUDI, Serving 10,000 or More Individuals and Using a Chemical Disinfectant.

(a) Routine Monitoring. Systems shall collect and analyze at least one water sample per quarter per treatment plant during normal operating conditions.

(b) Reduced Monitoring. Systems shall collect and analyze one water sample per year per treatment plant during normal operating conditions after completing one year of monitoring if the following conditions are met:

(i) The TTHM annual average is less than or equal to 0.040 milligram per liter and HAA5 annual average is less than or equal to 0.030 milligram per liter; and

(ii) The requirements of §B(3) of this regulation are satisfied.

(6) Subpart H System Serving Fewer Than 500 Individuals or Ground Water System Serving Fewer Than 10,000 Individuals and Using a Chemical Disinfectant.

(a) Routine Monitoring. Systems shall collect and analyze at least one water sample per year per treatment plant during the month of warmest water temperature and normal operating conditions.

(b) Reduced Monitoring. Subpart H Water Systems serving less than 500 individuals are not eligible for reduced monitoring. Groundwater systems on reduced monitoring shall collect and analyze one sample per 3-year monitoring cycle per treatment plant during normal operating conditions after completing 1 year of monitoring, if either of the following conditions is met:

(i) The TTHM annual average is less than or equal to 0.040 milligram per liter and HAA5 annual average is less than or equal to 0.030 milligram per liter for 2 consecutive years; or

(ii) The TTHM annual average is less than or equal to 0.020 milligram per liter and HAA5 annual average is less than or equal to 0.015 milligram per liter for 1 year.

(7) Systems on a reduced monitoring schedule shall resume routine monitoring at the frequency identified in §B(4), (5), or (6) of this regulation in the quarter immediately following the occurrence if:

(a) The system exceeds 0.060 milligram per liter for TTHMs or 0.045 milligram per liter for HAA5; or

(b) The system uses only ground water not under the direct influence of surface water and serves fewer than 10,000 people and exceeds an annual average of 0.080 milligram per liter for TTHMs or an annual average of 0.060 milligram per liter for HAA5.

(8) Systems on an increased monitoring schedule may resume routine monitoring if the TTHM annual average is less than or equal to 0.060 milligram per liter and the HAA5 annual average is less than or equal to 0.045 milligram per liter.

C. Location. If a system elects to sample more frequently than the minimum required, at least 25 percent of all samples shall be collected at distribution system locations representing maximum residence time. The remaining samples shall be taken at distribution system locations representative of at least average residence time in the distribution system and represent the entire distribution system, taking into account the number of individuals served, different sources of water, and different treatment methods. Each system shall monitor in accordance with a monitoring plan as set forth in 40 CFR § 141.132(f).

D. Compliance Date Extension for Treatment Installation. A system that is installing GAC or membrane technology to comply with this section may apply to the Approving Authority for an extension of up to 24 months past the dates in §K of this regulation, but not later than December 31, 2003. In granting the extension, the Approving Authority shall set a schedule for compliance and may specify any interim measures that the system shall take. Failure to meet the schedule or interim treatment requirements constitutes a violation of this regulation.

E. Repeat Sampling If Over MCLs.

(1) A water system which exceeds the maximum contaminant levels of Regulation .07F(1)-(4) of this chapter as determined under 40 CFR §§ 141.133 and 141.64(b)(2)(i) shall increase monitoring to once per quarter per treatment plant during normal operating conditions.

(2) Subpart H systems serving 10,000 or more individuals shall increase monitoring to at least four water samples per quarter per treatment plant during normal operating conditions.

(3) A ground water system serving fewer than 10,000 individuals shall increase monitoring to at least one water sample per quarter during normal operating conditions if either the TTHM annual average is greater than or equal to 0.080 milligram per liter or the HAA5 annual average is greater than or equal to 0.060 milligram per liter.

F. Compliance Determination and Notification.

(1) Quarterly analyses shall be averaged arithmetically and reported to the Approving Authority. Compliance with Regulation .07F(1)-(4) of this chapter shall be determined based on a running annual average of quarterly samples pursuant to the requirements of 40 CFR §§ 141.133 and 141.134.

(2) If a supplier of water has violated Regulation .07F of this chapter as determined by the average of sample results covering any 12-month period, the supplier shall notify the Approving Authority as required by Regulation .19 of this chapter and give public notice as required by Regulation .20 of this chapter.

G. Analysis. Analyses made to determine compliance with Regulation .07F of this chapter shall be conducted by one of the EPA-approved methods as set forth in 40 CFR § 141.131.

H. Increased Monitoring. The Approving Authority may increase the monitoring frequencies if it determines more frequent monitoring is needed, and the supplier shall comply with these frequency determinations.

I. Stage 2 Disinfectant Byproducts Requirements.

(1) Applicability. Community water systems and nontransient noncommunity water systems that use a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or residual disinfectant other than ultraviolet light, and certain consecutive systems, shall comply with the monitoring and other requirements of 40 CFR §§ 141.600- 141.629, Subparts U and V, to achieve compliance with MCLs based on locational running annual averages (LRAA) for total trihalomethanes (TTHM) and haloacetic acids (five) (HAA5) and with maximum residual disinfectant levels for chlorine and chloramine.

(2) Compliance Dates.

(a) Quarterly monitoring shall begin in the first calendar quarter that includes the compliance date specified in the table in §I(2)(b) of this regulation.

(b) If monitoring is at a frequency less than quarterly, sampling shall begin in the calendar month recommended in the Initial Distribution System Evaluation Report prepared under 40 CFR §§ 141.601- 141.602 or the calendar month identified in the monitoring plan developed under 40 CFR § 141.622, not later than 12 months after the compliance date specified in the following table:

If you are this type of system:	You shall comply with monitoring by:1
Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system
(i) System serving = 100,000 (ii) System serving 50,000-99,999 (iii) System serving 10,000-49,999 (iv) System serving < 10,000	April 1, 2012 October 1, 2012 October 1, 2013 October 1, 2013 if no Cryptosporidium monitoring is required under § 141.701(a)(4) or October 1, 2014 if Cryptosporidium monitoring is required under § 141.701(a)(4) or (6).
Other systems that are part of a combined distribution system
(e) Consecutive system or wholesale system	The same date as the system with the earliest compliance date in the combined distribution system.

¹The Approving Authority may grant up to an additional 24 months for compliance with MCLs and operational evaluation levels if systems require capital improvements to comply with an MCL.

(3) Monitoring and Compliance.

(a) Systems shall follow the monitoring requirements of 40 CFR § 141.620(c)(6) and (7) and § 141.64(b)(2), Subpart V.

(b) Systems required to monitor quarterly shall calculate LRAAs for TTHM and HAA5 using monitoring results required by this regulation. Compliance is achieved if each LRAA does not exceed the MCL. Systems that fail to complete four consecutive quarters of monitoring shall calculate compliance with the MCL based on the average of the available data from the most recent four quarters. Systems that take more than one sample per quarter at a monitoring location shall average all samples taken in the quarter at that location to determine a quarterly average to be used in the LRAA calculation.

(c) For systems required to monitor yearly or less frequently, compliance is achieved if each sample taken is less than the MCL. If any sample exceeds the MCL, systems shall comply with the requirements of 40 CFR § 141.625. If no sample exceeds the MCL, the sample result for each monitoring location is considered the LRAA for that monitoring location.

(d) Systems that fail to monitor are in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating a LRAA.

(e) Routine Monitoring.

(i) Locations. Systems shall monitor at not fewer than the number of locations identified as follows:

Source Water Type	Population Size Category	Monitoring Frequency1	Distribution System Monitoring Location Total per Monitoring Period2
Subpart H:	< 500 500-3,300 3,301-9,999 10,000-49,999 50,000-249,999 250,000-999,999 1,000,000-4,999,999 =5,000,000	per year per quarter per quarter per quarter per quarter per quarter per quarter per quarter	2 2 2 4 8 12 16 20
Ground Water	< 500 500-9,999 10,000-99,999 100,000-499,999 >500,000	per year per year per quarter per quarter per quarter	2 2 4 6 8

¹All systems shall monitor during the month of highest disinfection byproduct concentrations.

²Systems on quarterly monitoring shall take dual sample sets every 90 days at each monitoring location, except for Subpart H systems serving 500-3,300. Ground water systems serving 500-9,999 on annual monitoring shall take dual sample sets at each monitoring location. All other systems on annual monitoring and Subpart H systems serving 500-3,300 are required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. For systems serving fewer than 500 people, only one location with a dual sample set per monitoring period is needed if the highest TTHM and HAA5 concentrations occur at the same location and month.

(ii) Monitoring Plan. Systems shall develop and implement a monitoring plan to be kept on file for State and public review. The monitoring plan shall contain the elements specified in 40 CFR § 141.622, Subpart V, and be complete not later than the date the system conducts the initial monitoring required.

(f) Reduced Monitoring. Systems may reduce monitoring to the level specified in the table in this paragraph pursuant to 40 CFR § 141.623(a) -(d) when the following conditions are met:

(i) LRAA is less than or equal to 0.040 milligram per liter for TTHM and less than or equal to 0.030 milligram per liter for HAA5 at all monitoring locations, based on data collected pursuant to 40 CFR §141, Subpart V or L; and

(ii) Source water annual average TOC level, before any treatment, is less than or equal to 4.0 milligrams per liter at each treatment plant treating surface water or ground water under the direct influence of surface water, based on monitoring conducted under §B(3) of this regulation and in compliance with 40 CFR § 141.132(d).

(iii) Table.

Source Water Type	Population Size Category	Monitoring Frequency1	Distribution System Monitoring Location per Monitoring Period
Subpart H	<500	Monitoring may not be reduced.
	500-3,300	Per year	One TTHM and one HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; one dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.
	3,301-9,999	Per year	Two dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement.
	10,000-49,999	Per quarter	Two dual sample sets at the locations with the highest TTHM and highest HAA5 LRAAs.
	50,000-249,999	Per quarter	Four dual sample sets at the locations with the two highest TTHM and two highest HAA5 LRAAs.
	250,000-999,999	Per quarter	Six dual sample sets at the locations with the three highest TTHM and three highest HAA5 LRAAs.
	1,000,000-4,999,999	Per quarter	Eight dual sample sets at the locations with the four highest TTHM and four highest HAA5 LRAAs.
	>5,000,000	Per quarter	Ten dual sample sets at the locations with the five highest TTHM and five highest HAA5 LRAAs.
Ground Water	<500	Every third year	One TTHM and one HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; one dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.
	500-9,999	Per year	One TTHM and one HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter.
	10,000-99,999	Per year	Two dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement.
	100,000-499,999	Per quarter	Two dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement.
	=500,000	Per quarter	Four dual sample sets at the locations with the two highest TTHM and two highest HAA5 LRAAs.

¹Systems on quarterly monitoring shall take dual sample sets every 90 days.

(g) Increased Monitoring.

(i) A supplier of water shall increase monitoring to include dual sample sets once per quarter at all locations if a TTHM sample is greater than 0.080 milligram per liter or an HAA5 sample is greater than 0.060 milligram per liter at any location. There shall be 90 days between the samples. The approved sample period is based on the month that includes the peak historical month for the water system. Sample periods may include:

1) January, April, July, October;

2) February, May, August, November; or

3) March, June, September, December.

(ii) A supplier of water is in violation of the MCL when the LRAA exceeds the MCLs in 40 CFR § 141.64(b)(2), Subpart V, calculated based on four consecutive quarters of monitoring (or the LRAA calculated based on fewer than four quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters). A supplier of water is in violation of the monitoring requirements for each quarter that a monitoring result would have been used in calculating an LRAA if the system failed to obtain the monitoring result.

(iii) A supplier of water may return to routine monitoring if the supplier conducts increased monitoring for at least four consecutive quarters and if the LRAA for every monitoring location is less than or equal to 0.060 milligram per liter for TTHM and less than or equal to 0.045 milligram per liter for HAA5.

(h) Operational Evaluation Reports.

(i) A supplier of water shall provide Operational Evaluation Reports to the Approving Authority if operational evaluation levels are exceeded. A supplier of water shall calculate whether the operational evaluation level has been exceeded by using the standards established in 40 CFR § 141.626(a).

(ii) A supplier of water exceeds the operational evaluation level at any monitoring location where calculated values of TTHM and HAA5 exceed 0.080 and 0.060 milligram per liter as specified in 40 CFR § 141.626(a).

(iii) A supplier of water shall conduct an operational evaluation and submit a written report of the evaluation to the Approving Authority not later than 90 days after being notified of the analytical result that exceeds the operational evaluation level. A supplier of water shall conduct an operational evaluation in accordance with 40 CFR § 141.626(b). The written report shall be made available to the public upon request.

(4) Reporting Requirements.

(a) A supplier of water shall report the following information for each monitoring location to the Approving Authority within 10 days of the end of any quarter in which monitoring is required:

(i) Number of samples taken during the last quarter.

(ii) Date and results of each sample taken during the last quarter.

(iii) Arithmetic average of quarterly results for the last four quarters for each monitoring location (LRAA), beginning at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter. If the LRAA calculated is based on fewer than four quarters of data and it would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters, systems shall report this information to the Approving Authority as part of the first report due following the compliance date or anytime thereafter that this determination is made. If systems are required to conduct monitoring at a frequency that is less than quarterly, they shall make compliance calculations beginning with the first compliance sample taken after the compliance date, unless they are required to conduct increased monitoring under 40 CFR § 141.625.

(iv) Whether the MCL was violated at any monitoring location.

(v) Any operational evaluation levels that were exceeded during the quarter and, if so, the location, date, and calculated TTHM and HAA5 levels.

(b) Subpart H systems seeking to qualify for reduced monitoring or to remain on reduced TTHM/HAA5 monitoring shall report the following source water TOC information for each treatment plant that treats surface water or ground water under the direct influence of surface water to the Approving Authority within 10 days of the end of any quarter in which monitoring is required:

(i) Number of source water TOC samples taken each month during last quarter;

(ii) Date and result of each sample taken during last quarter;

(iii) Quarterly average of monthly samples taken during last quarter or the result of the quarterly sample;

(iv) Running annual average (RAA) of quarterly averages from the past four quarters; and

(v) Whether the source water TOC RAA exceeded 4.0 milligrams per liter.

(c) The Approving Authority may choose to perform calculations and determine whether the MCL was exceeded or if the system is eligible for reduced monitoring in lieu of having the system report that information.

(5) Recordkeeping Requirements. Systems shall retain any monitoring plans and monitoring results pursuant to 40 CFR § 141.33.

J. Requirements for Consecutive Systems. Consecutive systems that do not add a disinfectant but deliver water that has been treated with a primary or residual disinfectant other than ultraviolet light, shall comply with the analytical and monitoring requirements for chlorine and chloramines set forth in 40 CFR §§ 141.131"141.133 and shall report monitoring results pursuant to 40 CFR § 141.134(c).

Md. Code Regs. 26.04.01.15-2

Regulation .15-2 amended effective October 16, 2000 (27:20 Md. R. 1842)
Regulation .15-2 amended effective April 25, 2005 (32:8 Md. R. 743); December 14, 2009 (36:25 Md. R. 1956); March 7, 2011 (38:5 Md. R. 319); amended effective 43:17 Md. R. 957, eff. 8/29/2016