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Cross Connection Control
5310 Hawthorne Rd.
La Plata, MD 20646

Kristy McAndrew
Cross Connection Control Specialist

Monday - Friday
7:00 a.m. - 5:00 p.m.

Web Contact Form

Cross Connection Control Program

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The Cross Connection Control program is charged with maintaining the high quality of the County's drinking water by preventing actual or potential contamination of the potable (drinking) water with non-potable (contaminated) water and other sources of contamination. Backflow prevention devices and assemblies protect the water supply by making sure that your drinking water cannot flow back through your household or commercial plumbing system and into the County system due to either backsiphonage or backpressure.

Under Maryland Law, Business Occupations and Professionals Article 12-306(c)(2):

"Only a master plumber or journey plumber possessing certification shall be authorized to certify the installation and testing of mechanical cross connection control devices."

The County maintains a courtesy list of Registered Backflow Testers who are registered with the County and are authorized to perform backflow installation, testing and repair in Charles County.


This list of plumbing firms was assembled by the Charles County Department of Public Works–Utilities (DPW–Utilities) as a convenience to our customers. Inclusion on this list is entirely voluntary; the list is intended solely and simply to be a compilation of plumbing firms who have declared that they provide cross connection/backflow preventer related plumbing services. DPW–Utilities has verified that firms on this list are licensed and certified in accordance with Maryland regulations to perform these services. These firms do not work for, nor are they associated in any way with DPW–Utilities and DPW–Utilities assumes no liability for any work performed by a listed company.

DPW–Utilities does not endorse or recommend any company on this list, nor does it set pricing by these companies. DPW–Utilities suggests that customers obtain several estimates before hiring a plumbing firm to test your backflow preventer or provide any other plumbing services.

Irrigation Systems

Irrigation systems are a major concern for potential cross connections since fertilizers, weed control chemicals, pest control chemicals and animal excrement may be backsiphoned into your home's drinking water through the sprinkler heads unless your system is protected with a proper backflow preventer. Charles County requires the installation of an ASSE 1013 Reduced Pressure Zone Assembly (RPZ) for all irrigation systems. The use of an ASSE 1020 Pressure Vacuum Breaker (PVB) for irrigation systems is no longer permitted in the County.

The State of Maryland requires all testable backflow assemblies (including those used on irrigation systems) to be tested on an annual basis as a minimum. As noted above, the County maintains a courtesy list of plumbers registered with the County to perform backflow testing, including irrigation systems (please read the disclaimer above). If you contract with an irrigation company, make sure their plumber is registered with the County.

Irrigation systems cannot be placed in service until the backflow assembly has passed the annual test. Assemblies that fail the annual test must be repaired or replaced and re-tested before the irrigation system can be used. Should you decide not to use the irrigation system, the backflow preventer must be physically disconnected from the water supply system and the piping must be permanently capped. An irrigation system that has been winterized is not considered to be disconnected. Verification of a removed assembly is required.

If you are having an irrigation system installed, it is the homeowner's responsibility to make sure that the installer:

Hydrant Meter Program

The Cross Connection Control Specialist is also responsible for the County's Hydrant Meter Program. Charles County rents hydrant meters only to licensed contractors. The County does not rent hydrant meters for residential purposes. Hydrant Meter FAQs will provide more information on hydrant meters. Or you may contact the Cross Connection Control Specialist at 301-609-5606 to check on meter availability.

If you are an existing hydrant meter customer, report your monthly meter reading.