Overflow to Rain Garden
UV Disinfection is NSF Standard 55 Class B
Maximum rated flow at dose of 40 mJ/cm2 = 7gpm (two toilets flushing at once = 3.2gpm
Rain Aid mechanical fill valve is controlled by a weight set 12” above the tank outlet to pump. When the weight is floating in water, the valve is closed. When the weight is suspended in air, the valve opens and fills tank with 12” of potable water, leaving space for rainwater to fill the rest of the tank.
E. coli is a subgroup of the fecal coliform group. Most E. coli bacteria are harmless and exist in the
intestines of people and warm-blooded animals. However, some strains can cause illness. The
presence of E. coli in a drinking water sample usually indicates recent fecal contamination. That
means there is a greater risk that pathogens are present.
No detectable levels of E.coli were found in any of the LOG samples.
Total coliform bacteria are common in the environment (soil or vegetation) and are generally harmless.
Greatest total coliform levels in December recorded within 24 hours after rain event.
Residual chlorine in potable water back up reduced coliform levels to below detectable limits during summer months.
Turbidity is a measure of water clarity how much the material suspended in water decreases the passage of light through the water. Suspended materials include soil particles (clay, silt, and sand), algae, plankton, microbes, and other substances. These materials are typically in the size range of 0.004 mm (clay) to 1.0 mm (sand). Turbidity can affect the color of the water.
System on-line 11/8/2014. First monitoring date 11/17/2014.
18,240 gal catchment potential in average rainfall year. Only 7,461 gallons of potential in 2015.
600 sq. ft catchment area
4” of rain required to fill 1,320 gal cistern
1.3” of rain needed to supply avg. monthly water demand (430 gallons)
Full cistern = 1-3 month supply
Increase catchment area or increase storage to 2,500 gallons for 6 month supply
At $6.18/ccf, water delivered costs $0.01/gallon.
At $12/ccf water delivered costs just under $0.02/gallon
Cost of Santa Cruz Municipal Utility Water for Commercial Buildings in 2015 = $6.18/ccf.
Annual water savings is 5 ccf/year, or $30.90/year.
System Lifetime Savings = $601.47.
Without including maintenance costs (estimated at $150/year) the system has a payback period of 141 years.