Water quality
Currently, all Menlo Park Municipal Water’s drinking water is supplied by the Hetch Hetchy regional water system, operated by the San Francisco Public Utilities Commission.
The Hetch Hetchy system provides high quality drinking water to over 2 million people in the Bay Area. The SFPUC maintains a watershed control program that effectively limits or eliminates potential contamination to the water supply. The Hetch Hetchy water supply meets all federal and State criteria for watershed protection, disinfection treatment, bacteriological quality and operational standards, allowing the SFPUC and Menlo Park Municipal Water to provide customers with exceptionally high quality drinking water.
Menlo Park routinely monitors the distribution system for bacteriological quality, chlorine residual, general physical parameters and disinfection by-products. Regular testing is completed as required for lead and copper, samples are taken each week for bacteriological analysis.
Annual water quality reports
Lead service line inventory
Per the Lead and Copper Rule Revisions (LCRR) published by the United States Environmental Protection Agency (EPA), all water systems are required to complete a Lead Service Line Inventory (LSLI) by October 16, 2024, of both utility-owned (from the water main to water meter) and privately-owned (from the water meter to the property) service lines, to identify lines that contain or possibly contain lead.
Menlo Park Municipal Water (MPMW) completed its LSLI in accordance with the EPA's LCRR. No lead or galvanized requiring replacement service lines were identified. MPMW's LSLI was approved by the State Water Resources Control Board Division of Drinking Water.
Non-Lead Service Line Material Designation Statement
Menlo Park Municipal Water has completed the initial lead service line inventory required by U.S. EPA’s Lead and Copper Rule Revisions. The deadline for the initial inventories is October 16, 2024.
Through completing a historical records review and field investigations, Menlo Park Municipal Water has determined it has no lead or galvanized requiring replacement service lines in its distribution system. This includes any customer-owned service lines.
Menlo Park Municipal Water reviewed all applicable sources of information, including
- All construction and plumbing codes, permits, and existing records or other documentation which indicates the service line materials;
- All water system records, including distribution system maps and drawings, historical records on each service connection, meter installation records, historical capital improvement or master plans, and standard operating procedures;
- All inspections and records of the distribution system that indicate service line material, including inspections conducted during the course of normal operations (e.g., checking service line materials when reading water meters or performing maintenance activities); and
- All previous service line or meter replacements were conducted.
In addition to reviewing the above sources of information, Menlo Park Municipal Water used an alternative method to develop the inventory that was approved by the State Water Resources Control Board Division of Drinking Water on a case-by-case basis.
Menlo Park Municipal Water used a variation of the interpolation method. The interpolation method is used when the water utility can divide their service area into uniform groups, such as neighborhoods or tracts. Each uniform group shares multiple common characteristics, such as time period built, location, or contractor. The service line materials for each group are assumed to be similar. Water utilities physically verified a percentage of the homes in that group to interpolate or determine the service line material for the remaining homes.
Menlo Park Municipal Water began replacing all of its water meters in June 2024 as part of its Advanced Metering Infrastructure (AMI) project. During meter replacements, MPMW’s contractor physically inspected and documented approximately 74% of all of the customer-owned service lines. Best efforts were made to verify the material of all service lines, however, depending on conditions inside and around the meter box, this wasn’t always possible. All service lines inspected were verified non-lead. The specific material (copper, plastic, galvanized, other) is recorded in the lead service line inventory. No lead or galvanized requiring replacement service lines were identified.
Menlo Park Municipal Water continues to document service line material information obtained from normal operations, such as service line maintenance or future water meter replacements, after October 2024 and will update the initial inventory accordingly.
The results of the inventory are available upon request. Please contact us at water@menlopark.gov or 650-330-6750.
Backflow prevention (cross connection control) program
Menlo Park Municipal Water’s backflow prevention (cross connection control) program protects the public drinking water supply by requiring the installation and annual testing of backflow prevention assemblies per California Water Code Title 17. A cross connection is an actual or potential connection between a public water system and a non-potable source of water. Backflow is the undesirable reversal of flow of non-potable water into the water distribution system through a cross-connection. Properly installed and maintained backflow prevention assemblies protect the public water system and prevents water from flowing back into and contaminating the potable water supply. Assemblies are typically required for commercial, industrial, irrigation, fire, and new residential water connections.
For important information about backflow devices, who needs them, where to install them, and testing and maintenance requirements, refer to Menlo Park Municipal Water's backflow prevention (cross connection control) device installation guidelines(PDF, 241KB).
San Mateo County Environmental Health manages Menlo Park Municipal Water’s backflow prevention (cross connection control) program. The County establishes the list of certified testers, mails notifications to water account holders for annual testing, maintains records and performs site surveys as needed. For a list of approved backflow prevention assemblies, certified testers and frequently asked questions, visit the County’s website or contact the County at 650-372-6200.
Backflow Prevention Assembly
Backflow Prevention Map
