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How should utilities manage service lines downstream of master meters? 

Learn how to navigate complex master meter situations using takeaways from EPA guidance, master meter scenarios and best practices.

Eric Devlin
Allie Moss

By Eric Devlin and Allie Moss

Person wearing blue suit and light checkered shirt against dark background.
Eric Devlin EIT
Environmental Engineer
Person with shoulder-length brown hair in a black blazer and white shirt outdoors.
Allie Moss EIT
Environmental Engineer

EPA's Lead and Copper Rule Improvements (LCRI) require utilities to identify all water service line materials, including those downstream of master meters. A master meter is a single water meter that provides service to multiple buildings or units on a shared property. They are common in apartment buildings, mobile home parks, college campuses, gated communities, and commercial developments. Once water passes through the master meter, it travels through privately owned mains and service lines to reach individual buildings or units. In many cases, utilities have no visibility or control over the mains and service lines beyond the meter.

To comply with evolving Lead and Copper Rule regulations, how can utilities begin to identify service line materials downstream of master meters where record information is unknown? These situations typically fall outside of the traditional utility ownership and control, but they are still the water system’s responsibility for listing in the inventory. 

Diagram of water distribution lines to three buildings with labels for customer and system-owned lines.

The figure above outlines the EPA’s interpretation of one type of master meter configuration and the pipe sections to be included in an inventory. The EPA’s Inventory June 2023 Guide states that a community water system inventory must include “all service lines connecting the water main to the interior plumbing in a building, regardless of the actual or intended use." These include, for example, service lines connecting multiple units or buildings on a property.

In addition to including in the inventory, the EPA’s LCRI states that all Community Water Systems (CWSs) and Non-Transient Non-Community Water Systems (NTNCWSs) must make a “reasonable effort” to replace any lead or galvanized requiring replacement (GRR) service lines, even if they are beyond a master meter.

 

What do master meter scenarios look like?

One-to-many service line configuration

A utility-owned service line feeds through a master meter and then branches into multiple privately owned service lines to individual homes or units. This configuration is common in trailer parks or garden apartment complexes.

Responsibility: The utility must inventory and eventually replace (if needed) each service line to every building.

 

Private community distribution system

A master meter feeds a privately owned water main that serves multiple buildings with private service lines connecting from that main to each building. The entire internal network is privately owned. This configuration is common in campus-style developments.

Diagram of water service lines to three buildings, labeled C1, C2, and C3, connected to a master meter and a water main.

Responsibility: The LCRI and the guidance documents do not indicate that a water main must be owned by the water system, but the utility still has to inventory the service lines up to each building inlet. The EPA states that the pipe connecting the water main to the building must be inventoried no matter how the ownership is divided. In the above graphic, this would be C1, C2 and C3.

 

Best practices for identification

Identify potential master meter properties  

Use GIS data, meter sizes, and land-use records to flag properties likely served by master meters. Look for meters larger than 2", properties with multiple structures or shared ownership, and private communities without PWSIDs.

Clarify ownership and PWSID designation 

Determine if the development operates as a separate water system. If it has its own PWSID, it’s responsible for its own inventory. If not, the primary utility must include those service lines even if they’re fully on private property.  

Reach out to property owners and managers  

Send requests asking for construction dates of buildings and water infrastructure, service line material documentation, maps of internal plumbing networks, and confirmation of who owns what segments of pipe. Use at least two methods of contact (example: letter and phone call) and make four total communication attempts. EPA considers this to be “reasonable effort."

Offer to inspect 

Offer to conduct on-site inspections to confirm service line materials. A single visit can potentially resolve the status of dozens of unknown service lines.

Use aerial images and permits as supplemental evidence  

If property access is denied or not feasible, use aerial maps to count structures and predict service lines. Utilities can also use building permit dates and utility records to estimate materials.

Blue number 6 on a white background.

Update your inventory with likely material assumptions 

If you can’t obtain any information, assume there is one service line per building or unit. Use construction dates to assign likely materials of pipe (example: pre-state or local lead ban is potentially lead), and mark lines as unknown if verification isn't possible.

Blue number seven on a white background.

Notify customers of unknown materials 

Water systems must notify customers of unknown service line materials every year until they’re replaced. For master meter properties, this could mean sending notices to the individual tenants, as well as the property manager or owner. 

Blue number 8 icon.

Plan for replacements even without ownership  

Lead and GRR lines need to be replaced, regardless of ownership. If the utility can’t gain access, document outreach efforts, keep the line on your replacement list, and note the property as pending access (rather than removing it). Note that a water system is not required to pay for the replacement of a private lead service line.

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