Sunday, April 19, 2009
Working at the Earle-Harrison House on North Fifth Street, Greg and Kathy Riggs got used to curious conjectures about the house under construction next door, with its steep metal roof and stainless-steel silo out front.
Some imagined it was a new barn to serve the antebellum house museum. One asked if it was that new whiskey distillery that’s been in the news.
“Somebody from the Census came by today and said, ‘What’s that next door? It’s such a weird house. I don’t know where the front door is,’ ” said Kathy Riggs, who manages the Earle-Harrison House.
Here at last is the mystery solved: The house was designed and built by the Riggses as their “green” dream home. Water from the roof drains into a 10,000-gallon, vinyl-lined silo and is filtered through reverse osmosis and used for their inside needs. They plan to build a second cistern around back to collect water from the other side of the roof, using it to irrigate future landscaping.
As far as they or anyone from the city of Waco knows, it’s the first full-scale residential rainwater-harvesting system built in recent times. They plan to start using the tank this week, assuming the predicted weekend rains top it off. Their goal is to retain and use every drop that falls on their half-acre property and to zero out their city water use.
“We wanted to have the lowest impact we could have on the environment without spending tons of money,” said Greg Riggs, 60, a potter and retired state worker who works as a gardener at the Earle-Harrison House.
“It’s sort of a demonstration project. It’s also something that morally we wanted to do.”
Kathy Riggs said it seems hard to believe that enough rain falls on a house in Central Texas to meet a household’s needs. But as they calculate it, each inch of rainfall yields them 1,000 gallons. Waco gets an average rainfall of 32 inches, which adds up to 32,000 gallons a year or nearly 2,700 gallons per month. The Riggses use about 1,900 gallons a month inside and plan to use a separate system outside, where they will plant drought-tolerant plants.
“It is possible,” Kathy Riggs said. “It’s completely surprising to me. We’ve had four major rains this year, and we’ve got 9,000 gallons off just one small portion of our roof.”
The benefits of rainwater harvesting go beyond the savings on the household water bill. Home rainwater harvesting lessens the need to build new reservoirs in the middle Brazos basin, which is facing water shortfalls in the next 50 years. It also reduces the demand on city water-treatment plants in the summer months and helps reduce urban flooding.
The Riggses say taste is another reason to choose rainwater. The water is naturally “soft,” free of minerals such as calcium, and Kathy Riggs said it tastes “sweet.”
Practice goes way back
Rainwater harvesting is as old as civilization, and many Texas homes had cisterns before the advent of cheap, reliable public water supplies. But the practice is making a comeback, especially in areas of high growth and limited water, such as Austin, San Antonio and parts of California.
In Waco, World Hunger Relief Inc., Homestead Heritage and the new Greater Waco Chamber of Commerce building have rainwater-catchment systems.
But the Riggses’ system was the first residential above-ground cistern city planners and inspectors had ever encountered, and it prompted the Waco City Council in December to pass a zoning ordinance regulating such structures.
“We wanted to make it easier to do,” said Bill Falco, planning director. “That’s a green technology, and it’s not something we want to discourage. But we wanted to do something to control location and height so it would blend with other houses.”
The new ordinance requires the cistern to be tucked away in the side or back of the house, though Falco said that standard would not have applied to the Riggses’ house because it is set back from the street.
Part of the home
The Riggses, who designed the home, saw the cistern as an architectural feature of their house.
“We wanted it to look like a silo,” Greg Riggs said.
The Riggses concealed the gutters with some deft brickwork. At city inspectors’ urging, they also paid $1,200 for an engineered concrete foundation of 6 inches, with 30-inch footings — more strength than is required for cisterns over the San Andreas fault in California, Greg Riggs said.
The silo cost $16,000, and the piping, pumping, filtration and ultraviolet disinfecting system cost a couple of thousand more, the Riggses said.
But they said the high price tag shouldn’t scare people off. A simple fiberglass tank of the same size would cost only about $2,500, and the filtration system wouldn’t be needed for yard watering. And the Riggses were able to get a tax credit for installing green technology.
The Riggses also spent extra money to superinsulate their home with soy-based foam and add a heat pump and programmable thermostat. So far, their highest energy bill this year has been $130 for a 3,000-square-foot home. They recycle, compost and buy “renewable” electricity. And Greg said in coming years they hope to add solar panels, with an eye to “getting off the grid.”
It wouldn’t be the first time. During the back-to-the-land movement of the early 1970s, the Riggses lived in Montana, making pottery and living in a house with no electricity. They lit their cabin with kerosene lamps and heated it with cordwood even as temperatures dropped below minus 40 degrees.
They moved to Houston and then to Waco in the mid-1990s. They bought and renovated an old Craftsman bungalow on Colcord Avenue and started neighborhood programs such as the Sanger-Heights community garden and a children’s pottery workshop.
Now the Riggses are hoping to bring their eco-conscious ideas to the Earle-Harrison House, which is governed by the Pape Foundation. The home sits on six acres of lush gardens, which can cost more than $1,000 a month to keep watered.
“We’re in the process of a strategic plan, and there’s great interest in collecting rainwater,” Kathy Riggs said. “We’re trying to go green in as many ways as possible. It’s really exciting to think how we can save money on water. We have to change with the times.”
