Why is this Important?

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In 2012, Governor Brown signed legislation affirming California residents have the right to safe, affordable, and accessible drinking water. Most of California’s water is treated and filtered before it reaches residents, with the exception of the Hetch Hetchy Reservoir due to its high quality. California’s groundwater supply is stored in natural aquifers underground that replenish from runoff during wet seasons. Before reaching residents, drinking water goes through a treatment process in order to ensure there are no pathogens or other contaminants. However, chemically treating water can create byproducts that are hazardous in large quantities.

Water quality doesn’t only pertain to the water running through pipes into our faucets, it includes the water quality around us in the bay and ocean. Runoff from car-washing and pressure washing streets goes directly into the nearest stream, creek, or river without being treated, which finally reaches our bay and ocean.

Sanitary Sewer Overflows (SSOs) are occasionally caused by a blockage or a facility failure, though it is often heavy rain and runoff that causes sewer systems to exceed capacity. This process forces treatment plant operators to divert water if possible, and discharge sewage directly if needed. Runoff and overflow are dangerous to bay and ocean quality because of the quantity and mixture of what can be in the water. Raw sewage contains various bacteria, pathogens and solids, while runoff from residential and commercial areas contains chemicals and pollutants.

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What is a Sustainable State?

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In a sustainable state, the connection between water quality, use, and conservation will inform government policies and sustainable practices will be integrated into the everyday lives of citizens. Drinking water will be used selectively and water reuse will be a common practice. In homes, residents will have greywater systems that capture used drinking water and repurpose it in other areas of the home. Wastewater treatment plants will redistribute cleaned water through purple pipes and groundwater recharge. Green streets and parking lots will be the default design for new developments and municipal infrastructure. Utilization of pervious surfaces will allow polluted stormwater to be naturally filtered into the ground rather than flushed into waterways.

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Key Findings

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  • Contra Costa County had the highest spill volume in water year 2014, however, less than 25% of spills reached surface water.
  • In water year 2014 (10/1/13-9/30/14), over 151,000 gallons of raw or partially treated sewage spilled in San Mateo County, well below the 1.4 million gallons that spilled in water year 2013.
  • Overall, county beaches were less polluted in 2014 compared to 2014.
  • During dry seasons, only 10% of county beaches exhibit high levels of pollution, as opposed to wet seasons, when 33% of beaches are polluted by stormwater runoff.
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Drinking Water Quality

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About the Measurements: Trihalomethanes (THMs) and haloacetic acids are bi-products of the disinfection process. These disinfectants are used in drinking water to control microbial contaminants. They’re created when chlorine or chloramine react to organic or inorganic matter. THMs and haloacetic acids are monitored and measured because of the health risks they pose over long-term exposure. THMs can cause kidney and liver damage, while both THMs and haloacetic acids can increase the risk of cancer. Water suppliers try to limit the amount of pathogens in the water while simultaneously minimizing health risks associated with the disinfectant byproducts.

  • San Mateo County water districts have average levels of THMs, well below the federal level set by the Environmental Protection Agency.
  • North Coast County, San Bruno, and Westborough Water Dist. had the lowest ranges for THMs, measuring below 30 ppb (parts per billion).
  • No water districts exceeded the accepted federal levels for each tested contaminant.
  • Daly City and Hillsborough have not released their water quality reports for 2014 as of August 2015.
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Fluoridated Water

Fluoride is found naturally throughout California’s water resources and elsewhere, although the natural amount is not enough to promote oral health benefits. According to the California State Water Board, water systems are considered naturally fluoridated when levels are above 0.7ppm. The Center for Disease Control and Prevention states that introducing an optimal amount of fluoride in drinking water reduces tooth decay in children and adults by 25%. Optimal levels do range between 0.6ppm and 1.2ppm depending on outdoor temperature. Currently, all water districts in San Mateo County have levels of fluoride that range from not detected to 0.8ppm (parts per million). In order to give perspective on the unit parts per million, the SFPUC (San Francisco Public Utilities Commission) describes 1ppm equivalent to one cent in $10,000.
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Water: Bay and Ocean Water Quality

 

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San Mateo County Beach Report Card 2013 and 2014-Table

  • The Beach Report Card assesses water quality based on the health risk for beachgoers and assigns letter grades (A being best and F being worst). Beach scores are broken out by Summer Dry Period (April-October) and Wet Weather (sample collected during or within three days of a rainstorm).
  • 61% of beaches had a wet weather A or B grade in 2014, only 35% of beaches accomplished this in 2013.
  • 8 beaches received an A+ grade, up from 4 in 2013.
  • In dry weather, just 10% of county beaches monitored had water quality that posed a health risk for beachgoers, much better than the 33% in wet weather in 2014. This discrepancy in scores between wet weather and the summer dry period highlights the impact of storm water pollution. Storm water runoff, carrying untreated contaminants like motor oil, animal waste, pesticides, and sometimes sewage directly from our streets to our beaches is the largest source of pollution in our waterways.
  • Explore maps and historical data using Heal the Bay’s beach report card released in June 2015.

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  • Aquatic Park and Lakeshore Park again top the list of most polluted county beaches. Both beaches are lagoon-based with limited circulation potential and were also impacted by sanitary sewer overflows.

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A beach at Half Moon Bay. Photo courtesy of Shelby Scherer.

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Groundwater

Several groundwater basins reside below San Mateo County. The Westside San Mateo Basin is managed by the San Francisco Public Utilities Commission, which is in the process of new drilling projects that will provide a local source of fresh water. The San Mateo Plain Sub-basin is currently shared by a handful of users. Overuse of the basin resulted in land subsidence in the 1950s, and the region began to rely on water from the Hetch Hetchy system. In this time of water uncertainty, the Bay Area Water Supply and Conservation Agency (BAWSCA) has formed the Groundwater Reliability Partnership to evaluate the future use of the sub-basin. Potable recycled water recharge and brackish water desalinization are possibilities ripe for evaluation.
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Wastewater

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Sanitary Sewer Overflows (SSOs) are caused by unintentional discharges of raw sewage into bay and ocean water. This can happen through a variety of causes ranging from blockage and defects to power failure. Heavy rainwater can pour into cracked or clogged sewer pipes, causing untreated sewage to overflow into storm drains and area waterways. San Mateo County, with its aging sewer systems, is at heightened risk of sanitary sewer overflows. San Francisco Baykeeper, a local nonprofit, tracks sanitary sewer overflows and has used the Clean Water Act to file lawsuits against the greatest offenders.

Largest SSO by Total Volume Reaching Surface Water

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  • Contra Costa County had the highest spill volume in water year 2014, however, less than 25% of spills reached surface water.
  • In water year 2014 (running from: 10/1/13-9/30/14), over 151,000 gallons of raw or partially-treated sewage spilled in San Mateo County, well below the 1.4 million gallons that spilled in water year 2013.

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11_Nov2015

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Green Streets and Parking Lots

Green Streets integrate trees and water-absorbing landscapes or other pervious surfaces into streets, sidewalks, and parking lots to filter and dissipate stormwater. Traditional street design funnels stormwater directly into sewer systems that empty into watersheds untreated. This water is often polluted with trash, construction debris, pesticides and other chemicals. When new buildings are constructed or streets/sidewalks are repaired, green streets offer an opportunity to balance development through sustainable designs that mimic natural systems.

Several Green Streets projects have been implemented throughout the county.
• Brisbane City Hall, Rain Garden
• Serramonte Library Daly City, Rain Garden
• City of Burlingame, Donnelly Avenue Stormwater Curb Extension
• City of Burlingame, Burlingame Avenue Rain Garden & Curb Extension
• City of San Bruno, Stormwater Curb Extension
• City of San Carlos, Bransten Road Stormwater Curb Extension
• City of San Carlos, Old County Road Stormwater Curb Extension
• City of San Mateo, Delaware Street Vegetated Swales
• City of San Mateo Laurel Elementary School Stormwater & Safe Routes to School
• Moss Beach, Carlos Street Green Street & Fitzgerald Reserve Parking Lot
• Town of Colma, Hillsdale Boulevard Curb Extension

Visit the San Mateo Countywide Water Pollution Prevention Program website to learn more about stormwater management.

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Brisbane City Hall, Rain Garden
Photo by Matt Fabry
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Plastic Bags Banned

On Earth Day 2013, San Mateo County implemented a plastic bag ban for retailers. The ban required most retailers to stop distribution of plastic bags and replace them with paper bags. Retailers were required to charge 10 cents per bag, which then increased to 25 cents in 2015. The plastic bag ban has served many purposes, including pollutant reduction in storm water and runoff from littering. Moreover, the ban’s implementation made the topic of water quality more relevant for county residents.
Since the ban’s implementation:

  • +162% of shoppers use reusable bags.
  • +130% of shoppers hand carry items.
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