INDICATOR

 STATUS

Wastewater is the flow of used water a community generates. Generally, wastewater includes water from residential, business, commercial and industrial uses and is a mixture of water and dissolved or suspended solids.

This indicator tracks total citywide wastewater generation. Eventually the city would like this data to be disaggregated to reflect per capita generation, the contributions of storm drains and collections system and sectors of the economy, At present, current data reflects simply a citywide total. The indicator target is to reduce total wastewater flows by 15% below the 2000 baseline levels by the year 2010, 8.2 Million Gallons per Day (MGD).

This indicator had a dramatic drop in the early 1990's from 10.0 MGD to just 8.2 MGD in 1992. The flows stayed reasonably low until 1998, and have risen steadily since, topping off at  12 MGD in 2006.

Over the past few years, the integrity of  Santa Monica’s wastewater collection system has been secured by retrofitting the sewer lines and relining the system so that that there is no infiltration from groundwater or via manhole covers.   Still, the city continues to generate high levels of sewage not far below its water usage levels.  Though hard to establish conclusively, the relatively high proportion of wastewater to water use in the last two years probably stems from some of the following factors.

1.   Daily workforce population is roughly 300,000, triple the resident population. Workforce population may not contribute to the water use (due to bottled waters, bathing, irrigation & cooking at home, not at work) but does contribute to our wastewater flows. Any undocumented workers employed in the tourism sector don’t appear in our relatively static Jobs/Housing Balance, but nevertheless generate wastewater.

2.   On an average weekend, Santa Monica receives 500,000 visitors. This high level of tourism generates incremental wastewater from restaurant and hotel patrons, while not impacting water demand due to consumption of bottled water or other beverages, rather than tap water.

3.   Increased Monitoring System Sensitivity more accurately captures wastewater flows than before its implementation in 2002.  The previous system may have understated flows somewhat.

4.   Land Use Changes-Single Family Homes built on what were previously parking lots use proportionately less water, due to mandatory plumbing and irrigating efficiency measures required of new housing.  Still, those new housing units generate sewage.

City of Santa Monica’s wastewater collection facility is part of the Regional Transfer System established in  the 1970's by EPA which at the time recommended regional treatment centers as the norm.  Santa Monica’s sewage is treated at the Hyperion Facility which treats over 350 Million Gallons per Day.