County staff briefed the Board of Supervisors on May 20 about a proposed pilot program to install sub-meters for irrigation so residents who irrigate do not pay sewer charges on water that does not enter the sanitary system.

Patty Norris Barker (finance staff) said the county received 101 applications from residents interested in a meter-based adjustment. Barker and staff reviewed 14 months of usage records for each applicant and estimated each household’s baseline indoor use, then calculated the likely irrigation volumes that would be excluded from sewer billing if a sub-meter were installed.

Staff proposed a limited pilot — about 10 sites chosen to represent different service areas (Hopyard, Fairview Beach, Potomac Landing, Dahlgren) — to install cellular-connected sub-meters (which send readings via cell network rather than Wi-Fi). Vendors told staff they could refund the hardware if a cell-signal problem prevented successful data collection.

County staff and board members discussed possible cost-sharing structures. Staff noted installation and recurring data fees and administrative effort to adjust sewer bills manually for pilot participants. Staff proposed the customer pay meter hardware and a small monthly administrative fee, as has been done in other jurisdictions; in the initial year, a fixed reduction could be applied until sufficient data are collected to derive a more accurate credit.

Supervisor Robotham and others said representatives from affected neighborhoods should be included among the pilot sites; staff agreed and suggested selecting participants by geographic representation. Staff will return to the board with a list of pilot participants, estimated revenue loss to the sewer fund during the pilot and an administrative plan for reading and billing adjustments.