Back to the future
Our grandparents had the right idea about saving rain
August 09, 2007
This is one of two rainwater harvest collection storage containers installed at Victoria Educational Gardens to hold rainwater from the roof of the Officer's Club building. The Victoria County Groundwater District awarded grant monies to the Victoria Master Gardener Association for this system.
A cistern was dug and sealed over to look like a 1920s well with a bucket to fetch water. The old home collection area is gone from this cistern but the roof gutter provided rainwater to keep it full.
Do you remember going to your grandparents and seeing that big old cistern? Well, they had it there for a purpose: To collect water efficiently and use it conservatively to sustain plant life that was their food and for their drinking. Water was precious back then.

Over the years, it became abundant and cheap, but today it is once again a precious commodity. We buy it every day for $15.48 a gallon - $1.29 per 12-ounce bottle. And we thought gas was expensive.

Every living thing requires moisture to survive. Unfortunately, as our demand for it increases, our resources are declining. I think you will agree that this is a topic that deserves our attention and understanding. This article is not intended to solve every water-related problem, but to help you consider one resource your ancestors may have used.


Rainwater is one of the purest sources of water available. Its quality almost always exceeds that of ground or surface water. It does not come into contact with soil or rocks where it can dissolve minerals and salts nor does it come in contact with many pollutants that are often discharged into local surface waters or contaminate ground water.

Rainwater often has a low nitrogen content that provides a slight fertilizing effect for plants. It is also good for plants because it is free of salts and other minerals that harm root growth. As rainwater percolates into the soil, it forces accumulated harmful salts down and away from root zones, allowing roots to grow better and making plants more drought tolerant.

Rainwater is nearly perfect. It is soft so it can significantly lower the quantity of detergents and soaps needed for cleaning. Soap scum and hardness deposits do not occur using rainwater. There is no need for a water softener as there often is with water from a drilled well. And undesirable salts used by most water softener systems are not added to our wastewater treatment plants and reuse waters.

Also, with rainwater, water heaters and pipes are free of the deposits caused by hard water and should last longer, thus saving money.

Environmental Advantages

Rainwater harvesting promotes self-sufficiency and fosters an appreciation for water as a resource. It also promotes water conservation, while providing a new water resource. It also conserves energy as the energy input needed to operate a centralized water system is bypassed.

Local erosion and flooding from impervious cover associated with buildings is lessened as a portion of local rainfall is diverted into collection tanks. In this way, there will be less polluted storm water to manage.

Building a system

Building a rainwater harvesting system can be easy or difficult depending on your needs. A garbage can will capture water from an existing gutter or valley in your roof. This is easy and will be adequate for you for potted plants on the patio.

If you need more water, larger systems may include gutters, downspouts, filters and larger storage containers. A small pump may be necessary if gravity flow cannot meet your needs for a lawn sprinkler and drip system.

Whole house domestic consumption water systems will require additional filtering such as reverse osmosis or ultraviolet filtering. Water tests will also be necessary to insure the quality of the water. And, yes, there are people living on home sites in Texas today that are dependent on rainwater only.

How Much Can I Harvest?

Most people are really surprised by how much water you can collect with a single inch of rain.

To figure this, first you must determine the square footage of the roof or area from which you will be harvesting. To get this number, you must multiply the length in feet by the width in feet of your collection area. Multiply the square footage by 0.62 to get the number of gallons of water you will collect in a 1-inch rain.

Although last month exceeded all records, the average rainfall per month in the Victoria area is 3 inches. This is an average - some months you will get more, some months you will get none.

Based on the average 3-inch monthly rain, a typical 2,000 square foot home can collect 3,720 gallons or 1,240 gallons per inch of rain. That's a lot of water to use for watering plants and your garden when in need and a lot of water saved from the gutter.

Selecting a container

Storage containers may be made of polyethylene, fiberglass, wood, concrete or metal.

Containers may be located above ground or under ground. Consider that underground containers cost more to excavate and maintain. In addition, you will need a pump to get the water out of them.

Blocking sunlight from entering a container is critical so algae is not allowed to grow. If sunlight can penetrate the container walls, it might be necessary to paint the walls a dark color. A screen filter is usually placed in the area where the water enters the container to prevent mosquitoes, bugs and other debris from entering your tank.

Need More Help?

For more information on designing or building a rainwater harvesting system, contact your local County Extension office or go to

Or you can see two rainwater harvesting systems at the Victoria Educational Gardens, 333 Bachelor Drive at the Victoria Airport. The Victoria County Groundwater District has awarded grant monies for these as exemplary examples of rainwater harvesting for this area.

I am really pleased with the rainwater system I built. Do investigate rainwater harvesting on your home and business site. You may even determine that your grandparents' ways weren't so bad and that you will have gone back to the future.

The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas Cooperative Extension-Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, Texas 77901; or, or comment on this column at