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City of Austin Graywater and Rainwater Regulationstank:

What it means for you

On 10/21/15, DBL guest presenter Robert Stefani ([email protected]) of Austin Water, reviewed the latest in municipal Auxiliary Water regulations. The City adopted the 2012 Uniform Plumbing Code with local amendments, resulting in much more friendly regulations regarding rainwater and graywater. In the City of Austin, “auxiliary water” is water from a source other than the City’s potable water supply and includes: Rainwater, Graywater, A/C condensate and Reclaimed/Recycled water.

Graywater (from laundry, hand sinks, bath, shower; NOT from toilets and kitchen sink), accounts for approximately 50% of residential indoor water use. The average Austinite produces about 35 gallons of greywater per day.

Rainwater is water from the sky before it hits the ground. (Once it hits the ground it is stormwater and becomes regulated by the Watershed Protection Department.) Rainwater can be used to offset all or a significant portion of residential landscape water use, which accounts for almost half of the typical home water consumption.

Some of the highlights for single family applications include:

  • Rainwater can be used for a home’s potable water source. If you live inside the City Limits or are an Austin Water customer you are required to install a water meter on the municipal line, but you are not required to connect.
  • Unpressurized rainwater tanks of any capacity are not required to have an RPZ*. Unpressurized rainwater systems that are exterior outdoor non potable applications do not require a permit regardless of size.
  • All rainwater tanks of 500 gallons or more require City pre-approval for the Rainwater Collection Rebate Program. (The 500 gallon limit applies to each tank on the site)
  • Pressurized rainwater systems of any capacity require a permit.
  • Pressurized Rainwater and Condensate systems over 500 gallons require backflow protection, typically a RPZ, regardless of a potable water connection. Any pressurized Graywater system would require a backflow protection, typically a RPZ.
  • All graywater systems require a permit. The homeowner may pull a permit on a Laundry to Landscape system only. All other systems must pull a trade permit. The Auxiliary Water Permit is $160 ($35 at the time of our 10/15 meeting) or more depending on cost of project, one time.
  • If your graywater system is gravity fed (non-pressurized/no pump), you can mostly do what you want. Can do it yourself for under $250. No annual inspections.
  • Backflow protection is required for pressurized graywater systems, but not for gravity based graywater systems. Backflow protection is not required for rainwater and A/C condensate under 500 gallons regardless of pressure. Rainwater and A/C condensate, over 500 gallons, require backflow protection for pressurized systems but not for gravity based systems.
  • Professional design is required for all auxiliary water systems with the exception of the following:

(1) A rainwater catchment or condensate collection system for irrigating:

(a) landscaping of a single family dwelling where the system’s outlets, piping, and other components are located on the exterior of the single family dwelling, or

(b) landscaping other than that of a single family dwelling where the system’s maximum storage capacity is 500 gallons (1893 L).

(2) Gravity gray water systems having a maximum discharge capacity of 250 gallons per day (gal/d) (0.011 L/s) for a Homestead Permit (see note below) as described in section 103.1.3 of this Code for one- and two-family dwellings and townhomes.

(3) An on-site treated nonpotable water system for a single family dwelling having a maximum discharge capacity of 250 gal/d (0.011 L/s).

(4) A Laundry to Landscape graywater system.

No size exclusions

Pressurized graywater systems require an RPZ, engineering and annual inspections.

Graywater systems are currently prohibited in the Edwards Aquifer Recharge Zone (most places west of Loop 1), BUT there may be exceptions, so please talk to Robert Stefani.

*RPZ = Reduced Pressure Zone. A device to prevent backflow and contamination. Costs about $1500 and requires an annual inspection and fee.

For more information on rainwater, graywater and other auxiliary water use in the City of Austin, see Robert’s slide presentation (below) and



View Robert’s Slide Presentation: Auxiliary Water Overview

Additional note:

What is a “Homestead Permit” for Laundry to Landscape?

A homestead permit allows a homeowner (on an owned property receiving a homestead exemption) to pull the Auxiliary Water Permit and perform the work themselves, thus saving money. This differs from a “trade” permit in the fact that with a trade permit a third party, usually a plumber or engineer, must pull the permit and perform the work.

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