As repeatedly written, it is illegal to plumb recycled water to an existing irrigation system, especially if there is a possibility for recycled water and drinking water to mix. Recycled Water Fill Station users who decide to use their existing in-ground irrigation systems with recycled water risk losing their access to the free resource and could face fines or penalties for taking such steps.
Dublin San Ramon Services District (DSRSD) wrote in their ‘frequently asked questions’ about whether users can tie their recycled water tanks into an irrigation system –
No, and it is illegal to do so. Tanks, pumps, hoses, and equipment that contain recycled water must not be connected to any above- or below-ground, hard-piped irrigation systems, even if those systems are disconnected from your drinking water system. Any such connection violates the state’s drinking water regulations, the District Code, the Recycled Water Use Agreement you sign in order to use the fill station, and your city’s water code. Violators may be subject to fines and loss of fill station privileges.
The City of San Diego stresses this topic as well.
Do Not Connect to Irrigation Systems
For health and safety reasons, tanks, pumps, hoses and other equipment containing recycled water may not be connected to a dedicated irrigation system, even if that system is disconnected from your drinking water system. Illegal interconnections between the drinking water and recycled water supplies is prohibited. Any such connection violates the State’s drinking water regulations and the User Application and Agreement. Violators may be subject to loss of fill station privileges, fines, and other penalties.
What does this leave you with?
A pump and a hose with a wand, impact sprinkler or lawn spray. The above ground irrigation system is just that.
No inter-connecting of a completely separate irrigation system, no running recycled water through irrigation valves and stations, nothing fancy.
The only way around this, is to contact your local water agency and get a backflow preventer installed to their requirements and get it checked yearly for proper operation. There are fee’s associate with doing this, so make sure you take the permitted road first.