Wastewater

Wastewater
Virtually all of the water brought into your home is groundwater pumped from the Little Chino Aquifer, which is in overdraft. (link). It is possible to reduce groundwater pumping by reusing wastewater. So let's examine what happens to the groundwater used by urban and rural homes.

Landscape Water use:
Most urban and rural homes irrigate plants and lawns for seven months of the year. Irrigation water is either evaporated from the ground surface or transpired by plant leaves – this is lost water that does not return to the aquifer.

Urban Wastewater Use:
Water used inside urban homes is collected into the sewer and sent to the municipal wastewater treatment facility. Local cities treat their wastewater (effluent) to permit reuse and recycling. Some effluent is directly reused to irrigate golf courses; the remainder is allowed to recharge into the aquifer. In Prescott, about 55% of the groundwater pumped is recovered in the sewer. After treatment, 22% of groundwater pumped is directly reused on area golf courses, 28% of groundwater pumped is recharged (about 5% evaporates).

However, instead of dedicating the recharged water to the aquifer, Prescott, Prescott Valley, and Chino Valley use their recharge credits to maintain or increase groundwater pumping so there is no long-term benefit to the aquifer. Both Prescott and Prescott Valley use these recharge credits to support development. Furthermore, the recharge areas are far from the well fields, so there is no short-term benefit to the aquifer and water levels near the wells continue to fall. This is another reason why it is so important to conserve water used both inside and outside an urban home. Less water use in your home directly reduces groundwater pumping.

Rural Wastewater Use:
Rural homes obtain water from a domestic well and use a septic tank for on-site wastewater treatment. Effluent from the septic tank piped into an underground leach field to dispose of the wastewater. A significant portion of the septic effluent evaporates or is used by nearby trees and plants, so this is lost water. Some fraction of the septic effluent is recharged into the aquifer. The amount of recharge depends on the site and is impossible to determine precisely. The US Geological Survey uses a rough estimate of 35%, which is in the same ballpark as municipal recharge.

Because recharge is not very efficient in restoring groundwater, it is very important to conserve water used both inside and outside your home. Less water use in your home directly reduces pumping.