>>1833380People use "illegal" as hyperbole whenever there's gov't oversight.
"No state prohibits an individual citizen from collecting rain water.
"In 2012, the State of California passed Assembly Bill 1750, which enacted the Rainwater Capture Act of 2012, making it legal to collect rainwater so long as in compliance with the California State Water Resources Board requirements."
"In 2016, House Bill 16-1005 was passed, allowing residents to collect rainwater from a catchment system on their rooftops into two rain barrels, with a combined capacity of 110 gallons. "
"It is legal to harvest rainwater in Kansas, but a permit issued by the Department of Agriculture may be required."
"Nevada passed NB74 in June 2017, allowing for the collection of rainwater under the grant of a water right. Water rights must be used for its intended purpose or risk being revoked. "
"It is legal to harvest rainwater in Texas. There are several provisions in House Bill 3391 which should be noted, such as the requirement the catchment system being incorporate into the design of the building and the requirement to give a written notice to the municipality."