Drinking Water San Diego

If you are looking for the best drinking water San Diego has its share of shops to purchase it but we feel that the OB Water Store gives you the highest quality in the county with our 13 stage filtration system.
drinking water San Diego

Drinking Water San Diego

Drinking water San Diego has gone through many changes in the last 102 years, the San Diego water system has evolved into a very complex system. It now serves a population of 1.4 million people spread out over 370 square miles. The County of San Diego (CSD) treats imported raw water and local runoff water in three city water treatment plants, which have a combined capacity of 294 million gallons daily (MGD).

The CSD treats water by coagulation, flocculation, sedimentation, filtration and disinfection using conventional technologies. Currently, all CSD water treatment plants are undergoing modification to provide for the addition of fluoride to the potable water supply. To ensure safe and palatable water quality, the CSD collects water samples at its reservoirs, the WTPs, and throughout the treated water storage and distribution system.


Most of California’s water development has been dictated by the multi-year wet/dry weather cycles. Records indicate that extremely dry periods frequently last several years both locally and throughout California. During droughts, all imported and local water comes from reservoir or groundwater storage. Runoff in dry years is generally insufficient to meet environmental requirements and riparian water rights in imported water supply watersheds. The CSD has two major sources of water: imported and local runoff.

Imported water has historically accounted on average for 80% of the CSD’s annual water use, sources include:
The Colorado River via 300 miles of canals and pipelines.
The Sacramento River via more than 500 miles of canals and pipelines.
MWD’s Lake Skinner.
Imported water is delivered by federal, state and regional agencies. These are the United States Bureau of Reclamation, the State of California Department of Water Resources (CDWR), MWD, and SDCWA.

Imported raw water originates either from the Colorado River or the Feather River in the Sacramento River watershed. Precipitation on these watersheds has similar seasonal (winter/summer) and cyclical (wet/dry year) patterns to those of local watersheds. In most years, winter snow pack in the High-Sierras stores a significant amount of water until early summer. This “snow pack storage,” in combination with reservoir storage, helps to meet seasonal summer demand. To avoid water shortages during cyclical droughts, reservoirs are used to carry over (store) water from wet years to dry years.

Local runoff has historically accounted on average for 20% of CSD’s annual water use; sources include Nine (9) major CSD reservoirs which collect local runoff from watersheds covering more than 900 square miles. The annual average rainfall exceeds fifteen (15) inches in these mostly hilly and mountainous watersheds located outside of the city boundaries.

Below is the current condition of our water in San Diego conducted by SDcoastkeeper.org, this report shows the quality of our water is on a decline.

Water Quality in 2015 – How Drought Causes Worse Water Quality


Each month, the trained volunteer scientists on our Water Quality Monitoring team collect water samples from nine of San Diego County’s 11 coastal watersheds. We measure and test the samples in our lab and analyze the data to build an ongoing picture of our county’s water quality, uncover sources of pollution and inform better decision making to protect and restore San Diego County’s fishable, swimmable, drinkable water.

In 2015, all nine of the watersheds tested as Fair, Marginal or Poor on San Diego Coastkeeper’s Water Quality Index scoring system, all earning the same abnormally low scores as 2014.

Poor water quality puts significant stress on the vital rivers and streams that we rely upon for everything from flood control and natural filtration of toxins to wildlife preservation. Since our watersheds drain to the Pacific Ocean, these inland water quality issues also make our precious, economy-powering coastline less safe to swim and fish.

Very low water levels as a result of our fourth consecutive year of drought are partially to blame for the continued poor water quality scores. In 2015, we had more sites with water levels so low they were too dry to collect samples than any other year in our recent history.

Our 2015 data reveal low dissolved oxygen concentrations in 38 percent of samples and unhealthy levels of fecal indicator bacteria in 59 percent of samples, both common results of drought conditions. Urban runoff, sewage and industrial pollution are also likely significant contributors to the poor water quality.

Fecal Indicator Bacteria: Our Biggest Concern

Our water scientists use E. Coli and Enterococcus bacteria as indicators of water contamination by fecal material (animal poop or human sewage). These indicator bacteria are often present in some amount in our inland water, but high levels of them often indicate the presence of dangerous viruses and pathogens that can make you sick.

Over three quarters of our water samples in 2015 contained unsafe levels of fecal indicator bacteria. This means that our rivers and streams are carrying pollutants to the ocean that cause health problems like staph infections, ear aches, stomach issues, rashes, eye infections, and cysts — just to name a few.

When we collected samples 48 hours after a rainstorm in May 2015, every watershed but one exceeded unhealthy levels of Enterococcus. This is why the County’s Department of Environmental Health closes the beaches countywide after it rains — water quality is so poor that it becomes unsafe to swim.

This data also raises a question that we need more research to answer: “Is the drought reducing water levels so much that shallow, slow-moving and warm streams allow Enterococcus and E. coli to stick around much longer?” As in 2014, many of our testing sites in 2015 were so dry that we could not gather samples. We’re curious to explore this question with further research.

Our 2015 data revealed low dissolved oxygen concentrations in 38 percent of samples. This means our underwater wildlife is in significant distress. We can partially blame drought conditions for this problem, but urban runoff pollution is also a likely contributor.

When rain washes nutrient pollutants, like agricultural and lawn fertilizers, down storm drains and into our watersheds, it supercharges plant growth in our rivers and streams just like it does to grass in our yards. But this growth triggers a nasty chain reaction called eutrophication. Nutrient pollution can fuel massive, unnatural blooms of algae on the water’s surface that grow so big they block the sun from reaching plants below the water. When these plants die from lack of sunlight all at once, they begin to rot all at once too, producing an unnatural amount of bacteria that use up the dissolved oxygen that other wildlife depend on to breath. This puts stress on or kills our underwater wildlife.

Our 194 volunteer Water Quality Monitors gave a collective 1,808 hours to collect this important data. In 2015, we trained 74 new Water Quality Monitors and plan to triple our volunteer force by 2018.

Our Water Quality Monitoring program is the largest of its kind in the state and is one of San Diego Coastkeeper’s most powerful tools in protecting and restoring our water. The work of our passionate volunteers generates the vital, scientifically sound data our government agencies can’t collect, allowing us to keep a vigilant watch over San Diego County’s water quality.

In 2011, our Water Quality Monitoring team discovered a 1.9-million sewage spill upstream of the Los Peñasquitos Lagoon. The program provided authorities with the only available baseline water quality data and tracked the lagoon’s recovery. Water Quality Monitor testimony then contributed to a $12 million investment in basic sewage infrastructure, ending San Diego’s “sewage-spill-a-day” reputation.


This report for drinking water San Diego shows we need to be vigilant in our water conservation and take extra precautions in filtering our tap water for consumption or purchasing our drinking water from a reputable source.

The 2015 annual drinking water San Diego quality report just came out and it is a little scary with all the contaminants in the water and how the City of San Diego Public Utilities department use Chlorine, Ozone, and Ammonia Sodium Hydroxide along with a filtration system to clean our water, even though it meets or exceeds government guidelines, I feel hesitant to drink out of the faucet. We will be writing another article on this in the near future so stay tuned.

For information on our drinking water San Diego filtration system click HERE.