From Well Water to Rainwater

A Whole-House Water System
Beginner

Inside this Article

Nancy Poage-Nixon with her storage tank.
Nancy Poage-Nixon’s 5,000-gallon rainwater storage tank provides potable water throughout the year.
Metal roof collection surface.
The home’s metal roof was a convenient potable rainwater collection surface. Other materials are less desirable.
Metal gutter screens.
The first line of defense against contamination is to prevent debris from entering the system. One strategy (shown here) is to place a metal or plastic screen over the gutter. (Note that the asphalt shingles on this roof signifys nonpotable water systems.)
Permeable foam gutter inserts.
The first line of defense against contamination is to prevent debris from entering the system. Another strategy (shown here) uses permeable foam inserted into the gutter. (Note that the asphalt shingles on this roof signifys nonpotable water systems.)
A rainhead is the second typical line of defense.
A rainhead is the second typical line of defense against contamination. For this home, the roof height and lack of surrounding vegetation make this component optional.
A first-flush system is the third line of defense.
A first-flush system is the third line of defense, discarding the first wash of a new rain, including small particles and water-soluble contaminants.
Screened Floating Intake
The intake screen in this primary tank floats just below the surface, avoiding both “floaters” at the top and sediment at the bottom.
A float switch in the secondary tank.
A float switch in the secondary tank controls the pump that draws from the primary tank.
The 1,200-gallon secondary tank.
The 1,200-gallon secondary tank served as the original water storage. Now, it provides additional capacity and a place for incoming water to cool in the shade before entering the house.
A Grundfos pressure-booster pump.
A Grundfos pressure-booster pump (bottom) provides the house’s water pressure through a two-stage filter and ozone purification system (top).
Nancy Poage-Nixon with her storage tank.
Metal roof collection surface.
Metal gutter screens.
Permeable foam gutter inserts.
A rainhead is the second typical line of defense.
A first-flush system is the third line of defense.
Screened Floating Intake
A float switch in the secondary tank.
The 1,200-gallon secondary tank.
A Grundfos pressure-booster pump.

What do you do when your well runs dry? This proverbial question had real consequences for Nancy Poage-Nixon in Oak Hill, Texas, in the Hill Country outside of Austin. Development was encroaching from the east, and new subdivisions were drilling wells, tapping the already-stressed Edwards Aquifer. Although in its 28 years Nancy’s 438-foot-deep well hadn’t had any problems, in the summer of 2006, not a particularly dry year, its flow stopped.

Until then, Nancy had survived just fine with her well, although she’d never been particularly fond of the water that came out of it. The presence of sulfur meant that the tap water would often smell like rotten eggs. The water coming out of the karst limestone aquifer is also very hard, with a large amount of calcium and magnesium carbonates dissolved in it. This can have deleterious effects on household plumbing by building up in pipes and appliances, from hot water heaters to coffee pots, often shortening their lifespan. Hard water also doesn’t take soap well (it is “hard” to lather), making cleaning more difficult.

Previous to the drought, Nancy had installed a 1,200-gallon above-ground storage tank with an aerator to help pull the sulfur out of the well water and make it more palatable. Also before the drought, she had replaced her asphalt roofing with a new metal roof to help reflect sunlight and reduce home cooling costs. These two installations were going to be propitious when it came time to decide how to get water into her home after her well ran dry.

One local well-drilling company quoted $12,000 to drill through the limestone to the next layer of water in the aquifer. Of course, with new housing still going up and old wells going dry as the water table continues to fall, there was no guarantee that this deeper well would not dry up in the future.

Fortunately, drilling deeper was not the only solution. In the last decade, a few Austinites had set up whole-house rainwater catchment systems to provide all of their home’s water needs. Nancy teaches science at the local middle school, and she makes environmental ecology a part of her curriculum. Using rainwater for her home’s water needs would square with what she was teaching in the classroom and make a great example for her students.

After a bit of sleuthing, she found Chris Maxwell-Gaines at Innovative Water Solutions, who was happy to work with her existing well equipment and convert it to a rainwater collection system. Her metal roof was ideal for collecting water, as it leaves no residue in the rainwater it sheds. And the 1,200-gallon tank was a good start for storage. With these components—and if Nancy was willing to maintain her water-thrifty ways—the complete system would cost around $6,000, about half the cost of drilling a deeper well.

System Components

Nancy already had the metal roof, gutters, and 1,200-gallon tank. From there, Innovative Water Solutions opted for a “wet pipe” system that collects water in a similar fashion to a house’s typical drainage system. The downspouts are connected to sealed 4-inch PVC piping, which feed a large underground p-trap located between the house and a cistern. This is common practice when the cistern is located more than a few yards away from the house, so there are not elevated pipes traversing the yard. In contrast, a “dry pipe” system enters the cistern from above without going underground—when it is not raining, the pipes hold no water, negating concerns about harboring mosquitoes. Nancy’s wet pipe system includes a 2-inch pipe at the low point in the collection system that has a faucet with a slow drip to empty the pipe after a day or two of no rain, which reduces insect concerns.

Since her home has two stories, the gutters generally sit well above the tree line, so maintenance for tree debris isn’t a big concern. There’s no need for screens or other covers on the gutter, and her system doesn’t include a rainhead—an open box that separates out leaves and other debris from the rainwater. Eschewing gutter screens and the rain head saved money initially, but meant the frequency of cistern cleanouts likely needs to be increased (something done on a typical rainhead-based system about once a decade).

At the cistern, the pipe comes above ground, stopping at a “first-flush” diverter that siphons off the first 50 gallons or so from each rainfall event and directs it to the surrounding landscaping via a slow-drip irrigation system. Small leaves, bird droppings, dead insects, and other unwanted bacteria-containing debris that have built up on the roof since the previous rainfall come off in this first flush. Keeping it out of the cistern greatly reduces sediment buildup and potential water contamination. The first-flush diverter has a rubber gasket at its bottom with a small hole in it for dripping out the water between rainfall events, as well as a 4-inch cap that unscrews for debris removal.

Keeping light out of the cistern is crucial, or else microorganisms such as algae can flourish. The polyethylene tank exterior is UV-resistant, with an expected life of 30 years or so. This can be extended if the tank is shaded, saving the top from becoming brittle and potentially broken by hail or downed branches. An overflow outlet drains off excess water and an access hatch on top allows periodic cleaning and maintenance. Sunlight heats up the water in the tank in the summertime to upwards of 90°F, but Nancy is able to cool the water by first routing it through her original, shaded 1,200-gallon tank. While hot drinking water coming out of the tap is not ideal, preheated water reduces the energy load for her water heater.

Water is pumped from the main 5,000-gallon cistern to the smaller 1,200-gallon auxiliary tank, activated by a float switch in the auxiliary tank. A screened floating intake valve—reinforced vinyl tubing attached by a short chain to a black-plastic floating ball—pulls water from a few inches below the surface, thus avoiding floating debris and bottom sediment.

From the smaller cistern, a Grundfos MQ3-45 pressure-booster pump with built-in bladder tank provides household water pressure. Before entering the house, the piped rainwater is forced through a two-stage filtration system—a 10-micron sediment filter and a 5-micron carbon filter. Nancy’s water is then purified by an ozone injection system. Once thoroughly mixed with the water, the extra oxygen molecule kills any bacteria and viruses.

Reacting to the Drought

Although Nancy hasn’t increased her potable rainwater storage, she has added two 250-gallon tanks for use in landscaping. She also switched from grass that dies in drought to purple prairie clover for her small yard. This perennial native is drought-tolerant once established, with a deep root system capable of subsisting off erratic rainfalls and septic system discharge. As others fret over their wells running dry, Nancy can relax, knowing she has a more steady supply of water, and that she is helping recharge the diminishing aquifer.

Access

Stephen Hren is a writer and builder living in Durham, North Carolina. He is the author of Tales from the Sustainable Underground: A Wild Journey with People Who Care More About the Planet than the Law. Find out more at www.earthonaut.net.

Further Reading:

Catching the Cloudburst” by Heather Kinkade in HP125

“Free Rain: High-Tech, Hands-Off Rainwater Collection” by Doug Pushard in HP115

“Harvesting Rainwater” by Michael Durland in HP107

The Texas Manual on Rainwater Harvesting • twdb.state.tx.us/innovativewater/rainwater/docs.asp • Must-read publication 

Comments (1)

Rajendra Kumar's picture

Thank you for a very enjoyable read. I would like to see more DIY articles of this type and also solar distilling.

Regards
Raj (India)

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