From the Loveland Reporter-Herald (Pamela Johnson):
Colorado residents will be able to collect rainwater from their roofs to use in gardens and yards when a new law takes effect on Aug. 10.
Water officials expect that less than 10 percent of residents will use rain barrels, and each home is allowed to have two barrels totaling 110 gallons of water.
The amount is small enough that it should not cause any measurable drops in the water feeding into rivers to supply cities, farms and businesses locally and downstream, said Reagan Waskom, director of the Colorado Water Institute.
It won’t hurt utilities and those who hold water rights, and it will only help residents by supplementing the water available for their yards and promoting conservation, he said…
Residents likely will have to supplement their rain barrel water for their yards and gardens. However, the amount needed varies upon the size of yard and the type of vegetation, for example native low-water grasses versus a typical lawn.
Under the new law, each household can have two barrels to collect water from rain gutters or off the roof. That water must be used for outdoor landscaping, such as gardens or yards, and cannot be used indoors or for purposes such as filling a hot tub, according to guidelines from the Colorado State University Extension Service.
“You need a surface you can gather it from,” said Waskom, and the new state law specifies that the water must come from a rooftop.
The law also requires that the rain barrel have a lid that can be sealed to reduce evaporation but also to prevent mosquitoes from accessing and breeding in the standing water.
Health officials also urge people to completely drain and clean the barrel weekly or at least every month also to prevent a mosquito hotbed.
Home supply stores sell granules, called “Mosquito Dunkers” or “BTI granules,” that can be used to prevent any of the pests’ eggs from hatching, noted Katie O’Donnell, spokeswoman for the Larimer County Department of Health. These are commonly used in livestock water tanks and will not hurt wildlife or plants, she noted…
Colorado is the last western state to adopt a law that allows residents to collect rain water for their yards because of the demands upon water and the complex water rights system in place, Waskom noted. Those who hold the water rights worried that they would lose precious water supply and lobbied against the new law to prevent that.
However, water officials showed that the small amount of water diverted off roofs, which will likely be from a small number of homes, will not impact that water supply, according to Waskom.
And larger utility providers testified that the use of rain barrels could positively promote conservation.
Waskom added, “Hopefully it will make us more water conscious.”