Recycled Water Quality & Plant Needs

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