BELTON — For the past eight years, Karen Colwick has been teaching a rainwater harvesting workshop at the Bell County Master Gardener Learning Center, 1605 N. Main St. in Belton.
At the end of the three-hour class, students walk out proudly with their own 55-gallon rain barrels. This spring she was supposed to teach another one, but COVID-19 caused its postponement.
This week she was at the learning center, showing off various rainwater harvesting systems and talking about water. She became interested in the resource, she said, because her husband, Allan Colwick, was a hydrologist before he retired from the Soil Conservation Service.
For some of her classes, she lets an apple represent the vast amount of water on planet Earth. She quarters the apple and tells her students that three-fourths of it is sea water. And most of the fourth quarter is in ice caps. Of all the water on the planet, only about 1 percent is drinkable, she said.
This year’s rainfall in Central Texas has been good so far, she said, and is on track to reach the norm, about 32 inches. Lake Belton and Stillhouse Hollow Lake are full to overflowing, right now, she said.
“We’re in good shape here,” she said. “Other parts of the state, that’s not true. South Texas has had some droughts. West Texas was in bad shape, but they’re better now.”
People need to be smarter about their home irrigation system, she said. Seventy percent of our water usage in the summer time goes to lawn irrigation, she said, and sometimes the water is going into the street.
Rainwater harvesting is a step in the direction of water conservation, she said. The benefits of rainwater harvesting are that it reduces the use of municipal water, cuts down on runoff and prevents erosion, she said.
“The water is completely natural, so it is good for your plants,” she said.
It’s suitable for birdbaths and livestock, but not humans, she said. She’s hesitant about giving it to her dog.
“If it’s freshly collected, it’s good, but if it’s been sitting in the barrel for a while, I wouldn’t give it to my animals,” she said.
Whether it’s a 3,000-gallon tank or a 55-gallon barrel, the process of rainwater harvesting is the same, she said.
“You’ve got to have somewhere to collect, which is your roof,” she said.
That’s changed with the development of rain saucers, she said, which can serve as collectors.
The next thing needed is something to transport the water, which is usually a rain gutter, she said. Then you need a place to store the water, such as a tank or barrel. If you’re getting a lot of water and can use it, you can connect a lot of barrels together.
For her class, she uses food-grade barrels that are generally available for online purchase. The market has been tight lately, she said.
She showed a commercial rain barrel with a sealed top. That’s not good, she said, because the barrels need to be emptied and cleaned out once a year.
And white containers are not good, because they cause the development of algae, she said.
A 2,000-square-foot roof will collect 1,000 gallons of water for every inch of rain, she said. In a year, that could conceivably be 32,000 gallons of water collected.
The water is distributed to the garden or pot plants via a drip system, she said, but there’s not much pressure.
“For that reason you see a lot of barrels up on blocks or on some kind of stand,” she said.
The Bell County Master Gardeners have a 3,000-gallon storage tank at the learning center.
“We’re using it for the greenhouse,” she said.
The Master Gardeners want to use some of the water for their demonstration garden beds behind the AgriLife Extension building, she said, but haven’t figured out a way to get it there. They may have to set up another water collector closer to the beds, she said.
The Texas Tax Code exempts rainwater harvesting equipment from state sales tax, and the Texas Property Code prevents a homeowner’s association from prohibiting the use of rainwater harvesting systems, according to the Texas Water Development Board.
More rainwater harvesting information is available at TakeCareOfTexas.org and the Texas A&M AgriLife website.