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Sustainable Urban Landscape > Water Quality and Conservation


Don Schultz

Phone: (619) 660-4023


Sustainable urban landscaping



In a year of normal rainfall of just 10 to 12 inches, 80% to 90% of the water we use is imported by the Metropolitan Water District of Southern California (MWD), and the San Diego County Water Authority (CWA). Our water arrives via a 242 mile-long aqueduct bringing Colorado River water from Lake Havasu and originating from snow melt from the mountains of Utah, Wyoming or Colorado. Other sources include water which is captured in reservoirs north of Sacramento and released through natural rivers and streams into the Sacramento-San Joaquin Delta. The California Aqueduct then carries the water to State Water Project contractors like the MWD.

There are three water treatment plants in San Diego county; Otay Treatment Plant, Alvarado Treatment Plant, and the Miramar Treatment Plant. Water quality is sampled and tested by the Public Utilities Department's Water Quality Laboratory to determine if any quantity of contaminates are present.

Importing water over distances of hundreds of miles allows Southern California to enjoy a more comfortable life style but it comes at a cost. Water rates are relatively high as 80% to 90% of our water must be purchased and pumped to local storage facilities.

There are 10 reservoirs in San Diego County:

  • Barrett Reservoir
  • El Capitan Reservoir
  • Hodges Reservoir
  • Miramar Reservoir
  • Morena Reservoir
  • Lake Murray
  • Lower Otay and Upper Otay Lakes
  • San Vicente Reservoir
  • Sutherland Reservoir

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The City of San Diego - Water Quality

City of San Diego, Public Utilities - Recycled Water


Water conservation can be defined as any beneficial reduction in water use, loss or waste, as well as the preservation of water quality. Water efficiency is one tool of water conservation that results in more efficient water use and results in a reduction in the demand for fresh water. To ensure availability for future generations, the withdrawal of fresh water from an ecosystem or natural environment should not exceed its natural replacement rate. This practice of balanced usage is considered sustainable. Minimizing human water use helps to preserve fresh water habitats for local wildlife and migrating waterfowl, and reduces the need for new dams and other water infrastructure.


City of San Diego, Public Utilities- Water Conservation Program

In San Diego County, approximately 55% of the total water usage is for landscape applications. As of June 1, 2009, the San Diego City Government has issued a Stage 2 Water Alert. This Level 2 Drought Alert has mandatory water conservation restrictions that regulate the times, frequency and duration of landscape irrigation. The list of water use activities is broad-reaching and specific. Check to find if you are in compliance with these mandatory laws.


City of San Diego, Public Utilities - Water Level 2 Alert


Water quality generally concerns the physical, chemical and biological characteristics of water and is a measure of the condition of water relative to the use the intended use, either for human consumption, or for environmental purposes. The most common standards used to assess water quality relate to drinking water, safety of human contact, and the health of the environment. Clean Water Act set the standards and the criteria for the protection of aquatic life as well as for human health. The United States Environmental Protection Agency (EPA) limits the amounts of certain contaminants in tap water provided by public water systems.


 Guidance from the U.S. Environmental Protection Agency


Water quality depends on the local geology, ecology, and human uses such as sewage dispersion, industrial pollution, and overuse of reservoirs which may lower the water levels. The Safe Drinking Water Act authorizes EPA to issue two types of standards. Primary standards regulate substances and pollutants that potentially affect human health, and a set of secondary standards regulate aesthetic qualities, those that affect taste, odor, or appearance.


EPA- Ground Water & Drinking Water

NSF International is an independent, not-for-profit public health organization that writes public health standards for food, water, and consumer products. Known as Consumer Confidence Reports (CCRs), these reports provide customers with information about the quality of their drinking water supply over the past calendar year. In accordance with the EPA, each report must provide consumers with fundamental information about their drinking water. The NSF provides a guide to understanding and interpreting the CCR for your area.


NSF International

Annual water quality reports are available from each water district provider in San Diego County.


City of San Diego Water Utilities


Environmental water quality relates to water bodies such as lakes, rivers, and oceans. Toxins and high levels of certain microorganisms can be a health hazard for non-drinking purposes such as irrigation, swimming, fishing, rafting, boating, and other industrial uses. These conditions may also affect wildlife and habitat.

The Public Utilities Department has prepared the "Source Water Protection Guidelines for New Development Projects" as a guide for development in and around water supply watersheds aimed at protecting the local source waters.


City of San Diego Water Quality

County of San Diego, Dept. of Public Works—
Watershed Protection Program


Stated simply, a watershed is the area of land where all of the water that is under it or drains off of it goes into the same place. The quality of water stored in our reservoirs can be influenced by residential and commercial development, and human activities in the watersheds.

It is common for residential and commercial development to follow natural waterways, or to populate land found at the tops of hills and mesas. Both construction and maintenance practices, through mechanical grading, and the use of pesticides and fertilizers, can result in pollution and sediment build-up downstream from the source of the contamination.

Low impact development approaches and techniques help manage water and water pollutants at the source, preventing or reducing the impact of development on water and water quality.

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EPA Watershed Management

EPA Pollution Control

County of San Diego, Dept. of Public Works—
Watershed Protection Program


Storm water runoff is generated when precipitation from rain and snowmelt flows over land or impervious surfaces and does not percolate into the ground. Water from irrigation often flows into storm drains that spill into waterways and lakes that either supply potable water or that empty into the ocean causing pollution.

Ways to reduce surface runoff include:

  • Hard compacted soil and impervious surfaces like paving prevents water from percolating into the ground.
  • Runoff water flows into the storm drain system, into rivers & streams and eventually into the ocean and can cause flooding, soil erosion and pollution.
  • Landscape with improved soil to increase water penetration
    reduce the size paved areas or use porous paving like brick, stone or concrete pavers with gaps to allow water to reach the soil.
  • Use aggregate materials like gravel, sand, crushed stone or wood chips.
  • Pitch paving areas toward adjacent lawn or planting areas to capture any runoff.
  • Rain that falls on roofs can be channel to downspouts that are connected to underground perforated pipes that supply water to the landscape.
  • Rain gardens are low areas where runoff water collects to form a bog or mini-wetland garden.


County of San Diego, Dept. of Public Works (DPW)—
Storm water Regulations, Reports and Plans

Storm Water Program


Water from rain collection barrels, cisterns, retention basins are relatively common.

The benefits to the landscape and environment include:

  • Reduce water pollution from rainwater runoff.
  • Reduce soil erosion and improve the ability of water to infiltrate the soil.
  • Reduce dependency on the municipal water supply.
  • A cost savings on your water bill.
  • Garden plants, and lawn receive clean and free rainwater.
  • Save energy by reducing demand on the water supply.

Methods to save and reuse rain water include information from these sites:

Save Our Water Conservation Checklist

Metropolitan Water District of Southern California (MWD)—
Be Water Wise

A statewide public education program designed to educate Californians on the state’s water challenges— Save Our Water  

County of San Diego, (DPW)— Rain Barrel Information  

City of San Diego Public Utilities — Recycled Water


Career Technical Education

This web site is supported by Carl D. Perkins VTEA IC funds through the System. Office, California Community Colleges,
Grant #08-C01-020

Revised  July 28, 2014
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