Bend advisory group probes graywater use but flags limits on small lots
Loading...
Summary
City building and water staff briefed the Bend Water Advisory Group in February on graywater definitions, Oregon DEQ rules, permitting and conservation potential; members agreed multifamily and large-site reuse offer the clearest water savings while single-family outdoor offsets are modest and constrained by lot size, seasonality and maintenance.
At a February meeting of the Bend Water Advisory Group, city building and water services staff outlined how graywater reuse works, what state rules apply and where the measure might produce meaningful water savings in Bend.
"If it's appropriately collected and handled, graywater can be used safely for flushing toilets and irrigating certain trees and plants," said Jerry, a plumbing/graywater presenter with the building division, describing Oregon’s three treatment tiers and typical uses. His presentation referenced Oregon Department of Environmental Quality (DEQ) rules and the statewide alternate method (SAM) for building code compliance.
The briefing clarified three treatment categories recognized in Oregon: Type 1 (coarse-filtered or untreated graywater for subsurface irrigation), Type 2 (chemically or biologically stabilized water suitable for drip irrigation and landscape ponds) and Type 3 (disinfected reuse suitable for sprinklers or dust control). Jerry emphasized labeled purple piping, three-way valves to switch seasonal flows and the need for listed equipment and backflow protection to avoid contamination.
Dan, water conservation staff, presented local water-use data to examine conservation potential. He reported the utility’s average single-family residential account uses about 99.4 gallons per day indoors. Removing toilet use leaves roughly 73 gallons per account potentially available for reuse; over a typical 120‑day irrigation season that amounts to about 8,000 gallons — a modest offset against the program’s average outdoor use figure presented during the meeting (approximately 65,000 gallons by the metric shown).
That math led staff and members to a consistent conclusion: individual single‑family retrofits have limited capacity to meet seasonal outdoor demand, especially given Bend’s climate (frost and freezing ground), small lot sizes and setback constraints. Jerry noted ground freeze depth and higher local water tables can complicate outdoor subsurface systems and that DEQ approval is required before any outdoor distribution is permitted.
"We have to protect public health and our infrastructure," Jerry said, stressing that DEQ must review and approve outdoor distribution plans before the city issues permits and that some marketed consumer kits are not listed or appropriate for code compliance.
By contrast, multifamily and larger commercial or institutional projects appear more promising. Dan showed multifamily accounts average roughly 175,000 gallons per day with about 128,000 gallons potentially reusable once toilets are excluded; treated indoor reuse for toilet flushing can operate year‑round and yields a larger, more manageable water benefit. Members pointed to university buildings (OSU examples were cited) that have been pre‑plumbed for future treatment and internal reuse.
Discussion also covered operational and system‑wide impacts. Members raised concerns that removing large volumes of water from sewer influent could change sewage concentrations and treatment plant operations. Jerry and Dan said larger, centralized treatment systems would likely be state‑regulated and require an operations plan and oversight. The group discussed whether developers could install neighborhood‑scale systems to irrigate public right‑of‑way, but landscape architects cautioned such arrangements often fail without clear maintenance agreements and public‑private controls.
Questions about cost, permitting and transferability came up repeatedly. Presenters said plan review by the city’s building division is required for indoor reuse units and that DEQ review and a DEQ permit are prerequisites for outdoor reuse; some speakers noted DEQ permit transfer at property sale can create administrative burden for owners and buyers. Jerry said some installations have been identified during inspections and corrected; where equipment is sold but not listed for use, it must be verified and listed before approval.
Members and staff discussed incentives for larger developments, including whether system development charge (SDC) credits, fee relief or targeted incentives could make multifamily or commercial reuse financially viable. Several attendees urged staff to include a plausible set of system types (indoor toilet‑reuse, multifamily centralized reuse, and limited type‑1 subsurface applications for larger lots) in conservation modeling to advise council on cost‑effectiveness.
No formal decision or vote was taken. Staff said the graywater discussion will inform Dan’s upcoming water conservation program analysis and be reported to council as part of the biennial goal work. The group agreed staff should return with modeling that distinguishes new development, multifamily/commercial and retrofit pathways and that outreach/education for builders could lower barriers for residential adoption.
The meeting closed with an invitation for advisory group members to record short promotional clips for the city’s 100‑year water celebration. Staff posted slide materials and DEQ links for follow‑up and scheduled the next WAG meeting to focus on stormwater and the conservation annual report on March 4.
