Pennsylvania Code
Title 25 - ENVIRONMENTAL PROTECTION
Part I - Department of Environmental Protection
Subpart C - Protection of Natural Resources
Article II - Water Resources
Chapter 109 - SAFE DRINKING WATER
Subchapter M - ADDITIONAL REQUIREMENTS FOR GROUNDWATER SOURCES
Section 109.1304 - Assessment source water monitoring

Universal Citation: 25 PA Code § 109.1304

Current through Register Vol. 55, No. 13, March 29, 2025

(a) To enable the Department to determine if a groundwater system is using a groundwater source with fecal contamination, the Department may require a groundwater system to conduct monitoring for E. coli. If directed by the Department to conduct monitoring under this section, a water supplier shall:

(1) Collect a total of 12 samples from each groundwater source.
(i) The system may obtain written approval from the Department to conduct monitoring at one or more sources within the groundwater system that are representative of multiple sources used by the system. The Department will consider any factors that identify sources as representative of multiple sources drawing water from the same hydrogeologic setting.

(ii) For sources providing water to the public 12 months out of the year, groundwater systems shall collect one sample during each month.

(iii) For sources providing water to the public for less than 12 months out of the year, groundwater systems shall collect 12 samples evenly distributed over the operational period.

(iv) Samples collected under § 109.1303(a) (relating to triggered monitoring requirement for groundwater sources) may be used to satisfy the requirements of this subsection, if approved by the Department.

(v) If a groundwater system obtains an E. coli-positive groundwater source sample, the groundwater system shall perform a corrective action as described under § 109.1302(c) (relating to treatment technique requirements).

(vi) The groundwater system may discontinue assessment source water monitoring if the system demonstrates they provide at least 4-log treatment of viruses under § 109.1302(b)(1) or if directed by the Department.

(2) Collect groundwater source samples at a location prior to any treatment of the groundwater source.

(b) The following apply to an invalidation of an E. coli sample for groundwater source sampling:

(1) A groundwater system may obtain a Department invalidation of an E. coli-positive groundwater source sample collected under this section as follows:
(i) The system provides the Department with written notice from the laboratory that improper sample analysis occurred.

(ii) The Department determines and documents in writing that there is substantial evidence that the E. coli- positive groundwater source sample is not related to source water quality.

(2) If the Department invalidates an E. coli-positive groundwater source sample, the groundwater system shall collect a replacement source water sample under subsection (a) within 24 hours of being notified by the Department of its invalidation decision and have the replacement sample analyzed for E. coli. The Department may extend the 24-hour time limit on a case-by-case basis to 72 hours.

This section cited in 25 Pa. Code § 109.408 (relating to Tier 1 public notice-categories, timing and delivery of notice); 25 Pa. Code § 109.1302 (relating to treatment technique requirements); and 25 Pa. Code § 109.1307 (relating to system management responsibilities).

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