Keeping Manteca green may take a little gray as in graywater.

Graywater encompasses all “used” household water except for that used in toilets, dishwashers, or kitchen sinks.

The State of California building code allows for three such systems including one – laundry to landscape — that does not need a city building permit. Such systems cost an average of $200 — when installed by homeowners — and an average of $750 when installed by nonprofessionals based on a 2012 study by Ecology Action of Santa Cruz.

The laundry system has been shown in University of California at Davis studies to reduce household water use an average of 16 percent. Based on typical  water use in Manteca such a basic system could allow homeowners to recoup the costs in 18 months or less based on monthly water bill savings.

Larger water savings averaging 40 percent are realized through either a simple system or a complex system currently requiring a city permit costing $220. That’s on top of the installation cost that averages $715 for a do-it-yourselfer and $1,740 for a professional installation for a simple or branched drain system. The pumped systems that are more complex average $3,790 for a professional installation and $1,790 for a homeowner installed system.

In a bid to encourage residents to install graywater systems, the Manteca City Council on Tuesday will consider reducing the graywater system permit fee by 50 percent through July 1, 2015. The council meets at 7 p.m. at the Civic Center, 1001 W. Center St. That would make the permits $110 apiece. The permit fees are in place to recover the cost of the city processing permits and doing the subsequent follow-up inspection of work.

During the last fiscal year ending June 30, 2013, the city issued two permits for graywater systems.

Staff estimates the permit cost reduction could spur an average of one graywater system a month to be installed resulting in lost municipal revenue of $1,650.

The city is also hoping stepped up education about graywater systems could lead to a bigger jump in laundry to landscape systems. Since no permits are required the city has no way of tracking the laundry to landscape systems that are installed.

The municipal Community Development Department has free handouts on graywater systems.

The city handout notes:

• allowing water to soak into the ground is the most effective way to recharge groundwater supplies.

• households that have water softeners should not install graywater systems as the salt content is too high for trees, shrubs and bushes .

• water from dishwashers and kitchen sinks can’t be used as graywater.

• graywater should be drained to an area that is below at least two inches of mulch or gravel.

• graywater should not be used to irrigate any food crops.