Recycled water is created from treated wastewater, and because of this it contains certain constituents in greater concentration than in potable water sources. Fortunately, most of these constituents support plant growth and reduce the need for supplemental fertilizer.

Santa Rosa's recycled water provides the following essential nutrients for turfgrass and other plants:  

• up to 32 pounds of nitrogen per acre foot of recycled water delivered, which will offset 35% of the total nitrogen needed for turfgrass
• up to 6.8 pounds of phosphorus per acre foot of recycled water delivered, which will offset 20% of the total phosphorus needed for turfgrass
• up to 33 pounds of potassium per acre foot of recycled water delivered, which will offset 35% of the total potassium needed for turfgrass

The following table compares those elements and properties which are important to plants in Santa Rosa’s potable water and Santa Rosa’s recycled water. Also included is the drinking water standard established by the State of California for each constituent. Information about how these elements support plant growth can be found here:  www.ncagr.com/cyber/kidswrld/plant/nutrient.htm 

	Constituent or Property	Unit of Measurement	Santa Rosa’s Recycled Water*	Santa Rosa’s Potable Water**	Drinking Water Standard
Primary  (Health and Sanitary) Drinking Water Standard
	Copper	ppm	0.0034	ND	1.3
	Nitrate	ppm	13.6	0.48	45
	Nitrite	ppm	0.11	ND	1
Secondary (Non-Health and Sanitary) Drinking Water Standards or Unregulated Constituents
	Iron	ppb	59.2	ND	300
	Manganese	ppb	15.4	7.08	50
	Sodium	ppm	82.0	15.7	none
	Zinc	ppm	0.036	1.08	5
	Chloride	ppm	not tested	8.6	500
	Sulfate	ppm	not tested	11.3	500
	Total Dissolved Solids (TDS)	ppm	450	162	1000
	pH	pH scale	7.3	7.4	none
	Potassium	ppm	not tested	1.3	none
	Boron	ppb	376	235	1000
	Magnesium	ppm	20.0	13.1	none
	Phosphorus	ppm	3.7	not tested	none

*    Average of samples taken from January 2000 through December 2011.
**  From Santa Rosa’s 2011 Consumer Confidence report (based on 2010 sampling data) and Sonoma County Water Agency’s 2010 Water Quality Report
ppm – parts per million or milligrams per liter
ppb – parts per billion or micrograms per liter
NTU – Nephelometric Turbidity Units
ND – not detected