Milton Pogue has seen many a hot, dry Texas summer come and go. Ask him if he’s lived here long and he stretches his arm out to the southeast, index finger pointing past the far treeline. “I was born about two miles down the road 77 years ago.”
Himself a blend of the Old and New Texas, with a shiny, late-model, four-door sedan parked in front of a stone ranch house built in 1868, Mr. Pogue and his wife, Edith, have joined a growing number of Texans using an ancient idea to solve a pressing modern dilemma.
Two years ago the Pogues installed a rainwater collection system on their 110-acre ranch near Liberty Hill in northwest Williamson County. “I had a well out here, but my pump went bad and there was really very little water left in the well anyway,” Mr. Pogue said. “Rather than fool with all that I decided to have this system installed.”
He is still convinced he made the right decision. “We’ve had this system up and running two years and we’re really pleased with it,” he said.
Everything Old Is New Again
Harvesting rainwater for future use is certainly not a new idea. Evidence of such activity exists from humans in the Negev Desert almost 4,000 years ago. Ancient Romans installed cisterns, or collection tanks, under paved courtyards, gathering rainwater to supplement the aqueduct. Many older ranches in Texas still have stone and steel cisterns standing from a day when rainwater was a primary water source.
The idea is apparently catching on all over again, says Bill Hoffman of the Texas Water Development Board. He said several thousand rainwater harvesting systems have been installed in Texas this decade, as rising demand strains state water reserves.
“Rainwater catchment is never going to supply water on the scale of a reservoir system,” Mr. Hoffman said, “but it is a way for people to augment the existing water supply and ease demand on the system.”
For the Pogues, rain is the sole source of household water. They have a connection to the Chisolm Trail water supply, but Mr. Pogue says he only uses it to water his garden occasionally.
“I’ve never seen my tanks less than half full,” Mr. Pogue said. Two recent weeks of heavy spring rains topped off his tanks and he now estimates he and his wife have a six-month supply of freshwater. “And if it doesn’t rain for longer than six months, then we’ve got all kinds of other problems,” he dryly observed.
How Does It Work?
Rainwater harvesting systems range from a simple rain barrel to a complex arrangement of collection and circulation equipment. Most systems have five basic components. The first is an area to catch rain, usually a roof. Gutters and downspouts are used to transport the water to storage cisterns. Some type of conveyance system, which could be a pump or may simply be gravity, is needed to move the water. Finally, if the water is to be used for drinking and bathing, a filtration system is required to remove debris and bacteria.
The Pogues’ catchment and storage system are about as technologically advanced as they come and represent the high end of the market. With 3,600 square feet of catchment area on two barn roofs, they are able to capture approximately 1,800 gallons of water from each inch of rain.
Gravity draws the rain into extra-wide gutters and downspouts where it flows downhill into two large 10,000 cisterns. A standard swimming pool circulation pump and a cup of bleach in each tank once a week keep the water fresh and mostly free of bacteria.
A small wood-frame shed holds a smaller tank which pressurizes water to household standards and forces it through a five-micron sediment filter to remove the dirt and a three-micron carbon filter to remove most everything else. A micron is one-millionth of a meter or .000003967 of an inch. In other words, the filters screen out some pretty small stuff. The last filter the water passes through before it is pumped uphill to the residence is a chamber flooded with ultraviolet light, which kills any lingering bacteria that may be present.
Is It Safe To Drink Rain?
If you think about it, we all drink rainwater. The question is how far it travels and what happens to it before it comes out of the kitchen faucet.
Mr. Pogue said his water supply is regularly tested and exceeds safe drinking standards. And that is accomplished with fewer additives than most municipal water systems, Mrs. Pogue added.
“One of the things that appeal so strongly to us is that we know our water isn’t running over the ground where somebody has sprayed all these fertilizers and chemicals and pesticides all over the place,” she said. “In city water, they have to add so many chemicals to make it safe to drink but we don’t.”
Mr. Hoffman said water purity is only one of the many paybacks for the cost of installing an ambitious rainwater harvesting system such as the Pogues’. Rainwater also contains dramatically fewer dissolved salts and minerals, so no water softeners are necessary. Mrs. Pogue also reports they have experienced no lime build-up at all in their water lines, tubs, sinks or toilets since switching their water source.
Other, Less Ambitious Applications
Although cistern systems are generally less expensive to operate than typical water well, they are usually more expensive to install, which accounts for at least part of the reason more people have not experimented with catchment programs.
A good rule of thumb for estimating the installation costs of a full-blown collection, filtering, and pumping system for household use is about $1 per gallon of storage capacity.
Rainwater harvesters probably would not see a dramatic decrease in water costs either, since a back-up connection would still be desired in case of extended drought. An active connection to a community water supply usually carries a minimum monthly charge, even if no water is used.
Although municipal customers probably cannot justify the expense of installing new gutters, cisterns, pumps, and filters to capture rainwater for daily household use, many city dwellers are discovering the benefits of using harvested rain for landscape maintenance. Some Texas cities such as San Antonio actually supply free rain barrels for water customers in an effort to save water for use during the long, dry summer months.
In the Austin suburb of Round Rock, city manager Bob Bennet practically scoffs at some water-saving devices like low-flow toilets and showers, saying they have minimal impact on water consumption. Bennet said more than half of his city’s water goes to residential customers and more than half of that is for landscape maintenance.
“It’s actually pretty ironic that we go through all this trouble to capture all this water, treat it, and pump it all over the city just so people can squirt it on their lawn,” he said. Mr. Bennet said if people were serious about water conservation they would change the type of grass in their yard and find ways to reduce the amount of municipal water they feed their lawns.
Mr. Hoffman said many methods for better-utilizing rainfall other than cisterns can be used by almost anyone. Planting native species better adapted to the climate is one way to reduce supplemental watering. Using mulches and terracing sloping areas are other ways to make the most of rainfall when it occurs. These are just some examples he mentions from the Texas Guide to Rainwater Harvesting, a 60-page primer emphasizing small-scale residential and commercial applications. The guide was co-produced by the Austin-based Center for Maximum Potential Building Systems and the Texas Water Development Board and is available on-line for free at twdb.state.tx.us.
Texans who took the lead in the rebirth of rainwater harvesting in the 1980s often faced obstacles as tough as any drought. Skeptical bank executives refused to loan money to install such systems, especially for household consumption. City or county inspectors refused to permit rainwater harvesting due to unfamiliarity with the viability of cistern systems. That climate of skepticism is changing.
Mr. Hoffman noted that this year, two major projects in the Dallas-Ft. Worth area will probably have a significant impact on public perception of rainwater harvesting as a serious water source. Both a US Post Office and a new elementary school under construction will utilize harvested rainwater for landscape maintenance and for toilets.
He also pointed to Austin’s Green Builder Program which provides rebates for rainwater harvesting equipment as proof that governments both large and small have begun to change their attitude about rainwater harvesting from skepticism to curiosity to active promotion. Many banks and lending institutions are not far behind.
“It’s just a matter of educating people about the need to supplement surface and groundwater in Texas,” Mr. Hoffman said. “Once they understand that, then rainwater harvesting and other forms of conservation make more sense.”
Every gardener knows that nothing perks up a plant like a rain shower. Water from the garden hose just doesn’t measure up. Rain contains nitrogen, among other elements, that energizes the whole garden. We also know that, while we can build up the topsoil, add fertility to our plants, and even provide additional light to greenhouse plants, we can’t make water.
Growing populations and growing demands are making creating great stress on the water supply systems of this country. Increased pollution makes city water supplies and country wells more suspect. Whether you would like to collect rainwater to use as your only water supply or just to water your garden, there is a system that will meet your needs.