Rain Gardens and Cisterns

Use our WaterSaver Landscape coupons to construct your very own rain garden. SAWS also has a rebate for its residential customers who wish to have a large cistern to collect rainwater for non-drinking uses such as landscape watering. You can even combine the two for even more watering savings! But it’s not as easy as it seems, so SAWS has developed a complete program to walk you through it.

What's a Rain Garden?

 A rain garden is a great way to conserve water, reduce community flooding, improve the water quality in local streams and provide great wildlife habitat.

The basic idea is to locate them in an area where they will intercept run-off from your roof and other impervious surfaces before it runs into the street.

Use our WaterSaver Landscape Coupon to build yours.

When you construct a rain garden, you are basically building a 9 to 12 inch deep concave bed that holds water for a day or so and slowly drains through land absorption assisted by the right plants.

Choose a spot in your front or backyard, but the front may be best for intercepting rain before it hits the street. Make sure the area is at least 10 feet from your house and in full sun. Avoid utility lines and septic tanks.

If your home has gutters and downspouts, redirect the spouts toward the rain garden. As you layout your rain garden, think about where the rain will flow in and where it might overflow in case of a gully-washer. One way to alleviate overflow is to construct a dry creek bed through your rain garden to help diffuse the rain as it comes in.

As you choose your plants here are a couple of things to remember. The plants on the floor of your rain garden bed should be low-growing and able to tolerate sitting in water for 24 to 48 hours, and take the summer heat without supplemental irrigation. Woody plants or ornamental grasses will work for the sides of the garden.

Calculate the size. A half-inch rain on a 1,000-square-foot roof could produce more than 300 gallons. A 200-square-foot area that is six inches deep could hold about 750 gallons. Hey, that’s the exact size for the WaterSaver Landscape Coupon. Seems the WaterSaver Landscape coupon and RainSaver Gardens are made for each other!

This is a big, but doable, project. You will be moving lots of dirt to accomplish this project. Do your research. For more on how to build a rain garden including articles, designs and videos, dig in to our other resources right here on

Cistern Rebate Requirements and Regulations

Building and managing a large cistern at your home is a major long-term commitment similar to a swimming pool. You may want to consider an “Intro to Rainwater Harvesting” class to get the basics before you decide if this approach is right for you. Check our events calendar for rainwater harvesting classes.

This program is for large cisterns. You must have a minimum of 500 gallons of storage. The rebate is $1.00 per gallon up to $2000. You may have a cistern larger than 2,000 gallons but the rebate will max out at $2000. Rebates are issued after successful inspections. Checks are issued in the name of the SAWS account holder.

The application packet will require the following:

  1. SAWS account number and address.
  2. A statement that no potable in-ground irrigation will be present on site.
  3. A structural engineer’s signed, dated, and sealed final approval for a stable base where the cistern will be placed.
  4. A letter of intent to install a cistern of at least 500 gallons and schedule a site visit with a SAWS-approved RWH consultant.
  5. Square feet of the area to be irrigated, including vegetative swale (rain garden) size and placement to receive first flush and tank overflow.
  6. A basic planting plan.

You will need to have a Customer Service Inspection (CSI) by a state-licensed water safety inspector that will check your entire plumbing system. This is required by the Texas Commission of Environmental Quality ( TCEQ) because you will now have more than one source of water on your property. Depending on your set-up, the CSI will likely determine you need to install a high-hazard R/P backflow on your water service line behind the SAWS meter and have a licensed backflow inspector/tester inspect it. Both of these inspections and any required installations are solely at your expense. The final SAWS inspection is free.

Rebates are designed for permanent potable water savings. Adjacent landscaping must be able to survive with only natural rainfall and the harvested water stored in the cisterns. Potable water backup is not permitted. Properties may not have irrigation systems. A rain water harvesting calculator can assist you in determining cistern size.

Once you have built your cistern you will need to register it with SAWS per city code. This is a free online registration. It’s fast and easy, click here to register now.

How Cistern Rebates Work

Rebates are available to SAWS residential customers who install at least 500 gallons of storage on their property. The rebate is one dollar per gallon of storage, minimum $500. The maximum rebate is $2000 for 2,000 gallons of storage or more.

STEP 1: Attend a Rain Cistern Workshop

Attend an approved Large Cistern workshop offered by Alamo Community Colleges Eco-Centro. You will be responsible for any fees. Upcoming classes may be found on our Events calendar.

STEP 2: Submit a Cistern Application

Complete a cistern application packet (see below) and return to SAWS Conservation Department for approval. Once the Plan is approved, it will be accompanied by an official rebate offer.

STEP 3: Install your Cistern

Install your cistern according to the approved plan.

Hummingbird in flight

STEP 4: Customer Service Inspections (CSI)

Get a CSI inspection (at your own expense) to check all plumbing on the property. The inspector will likely require the installation of an R/P backflow, depending on set up. Links to a current list of inspectors and where to send SAWS your CSI report are in the section below.

STEP 5: SAWS Rebate Inspection

Once your CSI inspection has been submitted to SAWS call SAWS at 210-704-SAVE to schedule the SAWS final inspection to receive your rebate.

STEP 6: Rebates over $600

Rebates over $600 require IRS tax form W-9 (provide in the initial packet). Once you have passed inspection, submit the completed form to SAWS for your rebate to be issued.

The Fine Print

  1. Gallons are calculated as total storage on the property.
  2. The minimum size storage tank to be considered is 500 gallons.
  3. You may not have potable water backup into the tanks.
  4. You may not have an irrigation system in the yard.
  5. You are responsible for identifying and acquiring any City or HOA permits as required.