Water Resources Division Annual Report FY 2016-2017 | Page 8

Local Water Supplies (continued)
NON-POTABLE WATER PROGRAM
In 2012, San  Francisco established the Onsite Water Reuse
for Commercial, Multi-family and Mixed Use Development
Ordinance. Commonly known as the Non-potable Water
Ordinance, it added Article 12C to the San  Francisco Health
Code, allowing for the collection, treatment and use of
alternate water sources for non-potable uses in buildings. Since
2012, the Non-potable Water Ordinance has been amended
to allow for district-scale projects, where two or more parcels
can share alternate water sources. In 2015, Article 12C became
mandatory and now requires new development projects of
250,000 square feet or more of gross floor area to install and
operate an onsite non-potable water system.
San Francisco’s Non-potable Water Program was established
to create a streamlined permitting process and help designers
and developers look holistically at a project’s available
alternate water sources and non-potable demands. Common
alternate water sources include rainwater, stormwater,
graywater, blackwater and foundation drainage. Replacing the
demand for toilet and urinal flushing with non-potable water
can offset approximately 25% of the total potable water use in
a residential building, and up to 75% in a commercial building.
Other potential non-potable demands include irrigation,
cooling/heating applications, process water and clothes
washing. Using onsite non-potable water systems to meet
these demands can reduce potable water use anywhere from
50% to 95%.
RAINWATER
Precipitation
collected from
roofs and above
grade surfaces.
BLACKWATER
Wastewater
from toilets,
dishwashers,
kitchen sinks and
utility sinks.
GRAYWATER
Wastewater from
clothes washers,
bathtubs, showers
and bathroom sinks.
STORMWATER
FOUNDATION
DRAINAGE
Nuisance groundwater
from dewatering
operations.
6
Precipitation
collected from at
or below grade
surfaces.