Reclaimed Water Use in Los Angeles Plumbing

Reclaimed water — treated wastewater discharged at a quality sufficient for non-potable reuse — represents a regulated and increasingly structured component of Los Angeles's water supply portfolio. This page maps the classification system, applicable codes, permitting requirements, and professional responsibilities governing reclaimed water systems within the City of Los Angeles. It draws on state and local regulatory frameworks rather than offering installation guidance or professional advice.

Definition and scope

Reclaimed water, also called recycled water, is municipal wastewater that has undergone treatment to meet quality standards established by the California State Water Resources Control Board (SWRCB) and the California Department of Public Health, now administered under the California Department of Water Resources (DWR). California defines water quality categories in Title 22, California Code of Regulations (17 CCR §60301 et seq.), which establishes disinfection and treatment thresholds for each permitted end use.

In Los Angeles, the primary reclaimed water supplier is the Los Angeles Department of Water and Power (LADWP), which distributes Title 22-compliant recycled water through a dedicated purple-pipe distribution network physically separate from the potable supply. The Los Angeles County Sanitation Districts operate treatment plants, including the Tillman Water Reclamation Plant in Van Nuys and the Los Angeles-Glendale Water Reclamation Plant, that produce the effluent entering that network.

Scope and coverage note: This page applies exclusively to the jurisdiction of the City of Los Angeles and LADWP service areas. Unincorporated Los Angeles County areas, cities served by the Metropolitan Water District's member agencies but not by LADWP directly, and neighboring municipalities such as Burbank, Glendale, or Pasadena operate under separate agreements and distribution systems. Reclaimed water rules in those areas — and California's broader statewide advanced clean water reuse regulations — are not covered here.

How it works

Reclaimed water delivery in Los Angeles follows a sequenced regulatory and infrastructure pathway:

Wastewater collection — Sewage enters the municipal collection system managed by the City of Los Angeles Bureau of Sanitation (LASAN) and is conveyed to regional treatment plants.
Treatment and classification — Effluent undergoes secondary treatment, filtration, and disinfection. Title 22 defines three principal classifications: disinfected tertiary recycled water, disinfected secondary-2.2 recycled water, and disinfected secondary-23 recycled water. Only disinfected tertiary recycled water is approved for unrestricted landscape irrigation and certain industrial applications.
Purple-pipe distribution — LADWP conveys treated recycled water through a separate distribution network using purple-colored pipes, fittings, and valves — the visual identification standard required by the California Department of Public Health's Dual Distribution Guidelines.
Point-of-connection permitting — A property connecting to the recycled water distribution system must obtain a Recycled Water Use Authorization from LADWP and comply with Title 22, Los Angeles Municipal Code (LAMC) Title 64 (water), and any applicable site-specific use permit issued by the State Water Board's Division of Drinking Water (DDW).
Cross-connection control — Plumbing connecting to the recycled water system must be tested and physically isolated from potable lines. Backflow prevention assemblies are mandatory at every service connection, consistent with the USC Foundation for Cross-Connection Control and Hydraulic Research standards referenced in the California Plumbing Code (CPC Chapter 6).
Inspection and ongoing compliance — LADWP conducts annual inspections of recycled water use sites. The California State Water Board's General Order for Recycled Water Use establishes reporting obligations.

Common scenarios

Reclaimed water applications in Los Angeles plumbing fall into four recognized end-use categories under Title 22:

Landscape irrigation — Parks, golf courses, freeway medians, and commercial landscapes. LADWP operates more than 60 miles of purple-pipe infrastructure serving these applications in the San Fernando Valley and other corridors.
Industrial process water — Cooling towers, construction dust control, and concrete curing. Large commercial and industrial sites in manufacturing and construction zones access these supplies under site-specific use permits.
Toilet and urinal flushing (Title 24 compliance) — High-rise commercial buildings and large multi-family buildings in areas with purple-pipe access may use recycled water for fixture flushing, reducing potable demand. California's Green Building Standards Code (CALGreen, Title 24 Part 11) encourages but does not universally mandate this for retrofits.
Groundwater recharge — Indirect potable reuse through soil-aquifer treatment at spreading grounds managed by the Los Angeles County Flood Control District and DWR. This application operates outside the direct plumbing scope but affects the broader water supply system available to the region.

Greywater reuse — the separate category governing household laundry-to-landscape and branched-drain systems — is governed by a distinct regulatory regime. The greywater systems page addresses that classification separately.

Decision boundaries

Whether a reclaimed water connection is feasible, required, or prohibited for a given property in Los Angeles depends on five structural factors:

Purple-pipe proximity — Properties outside the existing LADWP recycled water distribution zone cannot access reclaimed water regardless of project intent. LADWP publishes a Recycled Water Service Area map, and extension of the network requires a separate capital project approval.

End-use classification — Not all Title 22 recycled water categories are interchangeable. Disinfected tertiary water is required for spray irrigation with human contact risk; lower treatment tiers are restricted to uses without that exposure pathway. Misapplying classification is a regulatory violation subject to State Water Board enforcement.

Cross-connection prohibition — The regulatory framework governing Los Angeles plumbing strictly prohibits any hydraulic connection between recycled water piping and potable supply lines. The California Plumbing Code and LAMC Title 64 both treat cross-connection creation as a code violation requiring immediate remediation.

Permit pathway — Installation of an on-site recycled water system requires permits from LADWP, plan check through the Los Angeles Department of Building and Safety (LADBS), and potentially a use permit from DDW. Licensed plumbers performing this work must hold a California C-36 Plumbing Contractor license (California Business and Professions Code §7026) and comply with any additional LADWP contractor approval requirements.

Water conservation mandates — During declared water shortage emergencies, the LADWP water service and plumbing obligations may include mandatory conversion or use directives affecting properties within purple-pipe reach. The Los Angeles drought and water conservation plumbing framework provides context for how shortage conditions interact with these obligations.

For properties evaluating integration of reclaimed water with broader green plumbing practices, the decision to connect must account for the full infrastructure, permitting, and ongoing compliance obligations detailed here — not only the upfront installation scope.

The Los Angeles Plumbing Authority index organizes the full scope of technical and regulatory plumbing topics across the city's residential, commercial, and infrastructure sectors.

References

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