Permitting Land Application: Choosing Between WDRs and Recycled Water Rules

What are the two permit paths?

WDRs regulate a discharge of waste. Water reclamation requirements regulate a use of recycled water. Both start the same way. Under Water Code section 13260, anyone proposing a discharge that could affect the quality of the waters of the state files a report of waste discharge with the Regional Water Board. From there they split:

• WDRs (Water Code section 13263): the Regional Board sets conditions that keep the discharge from degrading groundwater or surface water. Small domestic systems may enroll in a statewide general order instead of getting individual WDRs.
• Water reclamation requirements (Water Code section 13523): the Regional Board, after consulting the State Water Board, sets requirements for water used as recycled water, in line with the statewide water recycling criteria in Title 22, Division 4, Chapter 3.

A utility often holds both: WDRs or an NPDES permit for its treatment plant, and recycling requirements that cover the users downstream.

How does a Regional Board tell disposal from reuse?

By the primary purpose and the loading rate. The State Water Board's general order for recycled water use, Order WQ 2016-0068-DDW, draws the line plainly. It does not cover percolation ponds, excessive hydraulic loading of use areas, or any other method whose primary purpose is getting rid of treated wastewater.

The same order requires frequent uses such as irrigation to run at agronomic rates that account for soil, climate, plant demand and the nutrients already in the water.

So the practical test is the water balance. If the site can take the flow only by applying more water than the plants use, you are describing disposal, and WDRs are the likely path. If the water meets a real irrigation demand, it can qualify as reuse.

What treatment does each path require?

Under the recycled water path, the use sets the treatment. Title 22 section 60304 matches irrigation uses to quality levels:

• Disinfected tertiary: food crops where the water touches the edible part, parks, playgrounds, school yards, residential landscaping and unrestricted golf courses.
• Disinfected secondary-2.2: food crops whose edible part grows above ground and is not touched by the water.
• Disinfected secondary-23: cemeteries, freeway landscaping, restricted golf courses and nonedible vegetation with controlled access.
• Undisinfected secondary: orchards and vineyards with no contact with the fruit, fodder and fiber crops, and seed crops not eaten by people.

Under the WDR path, groundwater protection sets the treatment. The Regional Board writes limits from its Basin Plan and the state antidegradation policy, State Water Board Resolution 68-16. Nitrogen, salinity and depth to groundwater drive the design more than a use table does.

Which site conditions matter under either path?

Soil, groundwater, nitrogen and salt decide whether the site works at all. Neither path lets you skip them:

• Nitrogen loading: what the crop or landscape takes up, compared with what leaches toward groundwater.
• Salt: whether salts build up in the root zone or move into the basin. The State Water Board's Recycled Water Policy ties recycled water projects to the region's salt and nutrient management plan.
• Storage: where the water goes in wet months and low-demand months. The general order prohibits irrigating saturated soil.
• Runoff: recycled water may not leave the use area as surface flow unless another order allows it.

A storage pond is often where the two paths meet. Its size comes from the wet-weather months in the water balance, and an unlined pond can draw its own antidegradation questions from the Board.

What setbacks and public access rules apply to recycled water?

Title 22 section 60310 sets distances from domestic water supply wells by water quality.

• Irrigation with disinfected tertiary water stays 50 feet from a domestic well unless the listed conditions are met, and impoundments of it stay 100 feet away.
• Disinfected secondary-2.2 and secondary-23 water stay 100 feet away for both irrigation and impoundment.
• Undisinfected secondary water stays 150 feet away for both.

The same section keeps spray, mist and runoff out of dwellings, designated outdoor eating areas and food handling facilities. Use areas open to the public need warning signs at least 4 inches high by 8 inches wide. On a rural site with private wells, these setbacks can shrink the usable acreage more than any other rule.

Who reviews each path?

The Regional Water Board issues both, but the recycled water path adds the State Water Board's Division of Drinking Water (DDW). Title 22 section 60323 requires an approved engineering report before anyone produces or supplies recycled water, and DDW reviews it. Under the general order, the two boards fold the report's conditions into the notice of applicability.

California has nine Regional Water Boards, each with its own Basin Plan. Expect them to read a borderline project differently, and ask early.

When does a general order fit instead of an individual permit?

For reuse, an enrolled program; for small domestic disposal, the small systems order. Order WQ 2016-0068-DDW covers Title 22 uses other than groundwater recharge and potable reuse, enrolled through an Administrator such as the local recycled water agency.

For disposal, Order WQ 2014-0153-DWQ covers small domestic wastewater systems that discharge to land with a monthly average flow of 100,000 gallons per day or less. A system with subsurface disposal may be regulated by the county under the state OWTS Policy instead. Larger or more complex sites usually get individual WDRs or water reclamation requirements.

How do you pick the path before design?

Put the facts in front of Board staff before you choose treatment. A short checklist:

1. Build a monthly water balance: flow in, irrigation demand, storage and the wet months.
2. List each intended use and the Title 22 quality it needs.
3. Map domestic wells, surface water and public access areas against the section 60310 setbacks.
4. Check depth to groundwater, soil infiltration and the Basin Plan objectives under the site.
5. Find out whether a recycled water Administrator already serves the area.
6. Meet the Regional Board with that package, then size the plant.

That order matters. The wastewater engineering for a California site follows from the path, not the other way around.

Limits of this article: this is general education on California rules as of October 2026. Each Regional Board applies its own Basin Plan, and the path for a given site is the Board's call, so confirm it with the Board before design.

Frequently asked questions

Is land application faster to permit than a surface water discharge?

Not by default. It avoids an NPDES permit, but it still needs a report of waste discharge and either WDRs or recycling requirements, with their own review. Our post on the 120-day WDR rule in California covers the filing timeline.

Does every recycled water project need a Title 22 engineering report?

Every producer or supplier of recycled water needs an approved one under section 60323. A user connecting to an existing program is usually covered by the supplier's report and follows the supplier's rules for its site.

Can one site hold both kinds of requirements?

Yes. A facility can irrigate under recycling requirements in the dry season and send surplus water to disposal areas regulated by WDRs. Each part has to be described and permitted for what it actually does.

I'm developing a rural subdivision in the Central Valley with its own package plant, and I want to irrigate the common areas with the effluent. Which permit do I need?

Start with the water balance. If the common areas can use the flow at agronomic rates, the irrigation is a recycled water use, and the common areas need disinfected tertiary water under section 60304. Any surplus you cannot use is disposal and needs WDRs. Take both to the Central Valley Regional Board early.

Can I design the treatment plant before the path is set?

It is risky. A plant sized for disposal may not reach disinfected tertiary quality, and a plant built for reuse may still face groundwater limits under WDRs. Settle the path first.

Related resources

• The Title 22 Engineering Report: The Real Bottleneck in California Recycled Water Projects
• Understanding Order WQ 2016-0068-DDW: California's General Recycling Authorization
• Local Sewer Connection vs. State Permit: When a California SIU Permit Is the Faster Path
• The Six Month Rule: What California's NPDES Timeline Actually Says and What It Does Not

Choosing a land application path for a California site?

We build the water balance, the use list and the site constraints first, then design the treatment and land application system to the path the Regional Board will actually apply. Tell us about your site.

We specialize in:

• Wastewater treatment plant design
• Land application and recycled water system design
• Title 22 engineering reports
• WDR and recycled water permit applications
• Storage pond and irrigation system design
• Site civil engineering for land development

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com