PURCELLVILLE, Va. October 25, 2016— The Town of Purcellville is pleased to announce that after months of repairs, testing, and regulatory review, the Town’s well at Hirst Farm has been placed back in service in the Town’s Public Water System (PWS). Town staff has worked closely with the Virginia Department of Health’s Office of Drinking Water (VDH) to prepare a plan of operations and monitoring. This plan, approved on Friday, October 21st, allowed the Town to resume well operations on Tuesday, October 25th.
In July 2015, a test of the untreated (raw) water source indicated the presence of E.coli at the Hirst Well. Although the treated (finished) water remained safe to drink and had no indications of contamination, the Town took the Hirst Well out of service due to additional positive results from the untreated water samples.
For the past 15 months, staff has worked with a consultant and VDH to determine possible sources of the fecal coliform in the raw water. During this phase, it was identified that the concrete pad surrounding the top of the well had cracked and was likely allowing contaminated surface water to enter the well. The Town Council approved the use of unassigned Fund Balance to fix the well, and staff had contractors perform the following repairs to the Hirst Well: fixed the concrete pad; re-grouted the casing of the well, which had shown indications of cracking; and chemically cleaned and brushed the well.
Staff began running the well in June 2016 (while disconnected from the PWS) to ensure the well was ready for use. In September, staff conducted numerous bacteria tests and all test results were negative for bacteria/E.coli.
Based on the testing to-date, staff and the consultant are confident that the well has been properly fixed, sealed, and protected from future contamination, and VDH has approved the reinstatement of the well. Nonetheless, in order to ensure the continued safety of the Town’s drinking water, the Town and VDH have imposed the following conditions on the Hirst Well upon its reinstatement:
• Twice-per-week “most-probable-number” (MPN) testing of the well for total fecal coliform until 20 testings have been achieved.
• Only run the well during the hours of 6:00 am to 6:00 pm (Monday-Friday), unless dedicated staff can monitor on weekends.
• Call out parameters set by chlorine analyzers. The system will alert staff if chlorine levels fall below 0.7 mg/L. This will allow staff to respond to the well station and investigate why chlorine levels have dropped below the optimum range of 1.5-2.0 mg/L. In the event the chlorine levels fall below 0.5 mg/L, the system will automatically shut off the well. This procedure ensures that water always has sufficient levels of chlorine to kill the E.coli bacterium, should any recur in the raw water.
• Run well at a rate of approximately 50 gallons per minute (gpm) to achieve 36,000-40,000 gallons per day. While this is less than the original flow of the well, it still achieves the daily production amounts by running for up to 12 hours per day.
The Hirst Well is an important component of the Town’s PWS, representing approximately six percent (6%) of the total water production for the Town. The well also provides additional pressure and water flow for the southwestern end of Town.
The Town remains committed to maintaining a water system that has redundant sources (both well and surface water), provides safe drinking water to all customers, and is aesthetically pleasing to consumers. Residents are welcome to contact the Town Manager or Director of Public Works at 540-338-7421 with any questions or concerns.
