Contact Us


Cal Poly manages water resources to ensure adequate supply, meet or exceed health standards, reduce environmental impact and cost, and conserve and protect natural resources.

Water Sources

Cal Poly's water is derived from two primary sources: Whale Rock Reservoir and local groundwater. Water from Whale Rock reservoir is delivered by the City of San Luis Obispo; local groundwater is provided via six agricultural wells owned and operated by the University.  Cal Poly has water rights for both ground water and surface water.  Ground water is pumped from six agricultural wells located on University land and is limited by relatively shallow, low capacity aquifers, especially during drought years.  By State Water Resources Control Board permit, Cal Poly owns surface water rights to Brizzolara Creek on the Cal Poly campus, and to Old Creek which supplies Whale Rock Reservoir near Cayucos. To view raw water tracking data, download the linked XLS file.

reserviorAlong with the City of San Luis Obispo and the California Men's Colony, Cal Poly was one of the original developers of the Whale Rock Reservoir, and therefore retains rights to 34% of the reservoir capacity.  Since Cal Poly owns adequate water rights to meet campus needs, the University does not pay for its water supply, but does pay fees to the City of San Luis Obispo for delivery and treatment.  By investing capital funds to purchase a capacity share of the City water treatment plant, Cal Poly receives a discounted rate for treatment costs. 

Surface water is delivered by the City of San Luis Obispo from both Whale Rock Reservoir and Salinas Reservoir.  The City of San Luis Obispo operates Whale Rock Reservoir and determines the most economical way to deliver both treated water for domestic consumption and raw (untreated) water for agricultural use.  Whale Rock water is generally used for domestic use.  Untreated Salinas water is generally delivered to Cal Poly for agricultural use. Both types of delivered water are applied against Cal Poly's Whale Rock water rights. 


Cal Poly's water use for both landscape and crop irrigation is directly related to annual rainfall, and how rain events are spread out over the seasons. Due to San Luis Obispo's Mediterranean climate, there is typically very little or no rainfall from May through October. To view raw water tracking data, download the linked XLS file.

Back to top


droughtBeing good stewards of water resources and eliminating waste are recognized to be among Cal Poly's most important sustainability efforts. Throughout the years, Cal Poly has been an excellent steward of its water resources, having implemented hundreds of water conservation measures. Since 2003, total campus water usage has remained nearly flat despite a 60% growth in building square footage and 100% growth of on‐campus residency over the same period. Even with these past accomplishments, ongoing drought coupled with the Governor's mandate to reduce 25% of personal (potable) water use by February 2016 required a acceleration of efforts.

To achieve the reduction mandates, a Drought Planning Group was convened to identify short and long term conservation measures and operational changes. This group included representatives from Facility Management and Development, Environmental Health and Safety, University Housing, Associated Students Incorporated, the Cal Poly Corporation, and CAFES Ag Operations.

While the Governor's 25% by 2016 reduction goal applied to personal water use only, Cal Poly's Drought Planning Group felt that in order to honor its commitment to resource stewardship and act on behalf of the water that the Governor's goal should apply to ALL Cal Poly water uses and expanded the scope to include landscaping, agriculture, and building water use.

From the Drought Response Plan, three primary short term conservation measures and one longer term infrastructure measure were prioritized. The short term conservation measures include building plumbing systems, automated landscape irrigation management, and precision-irrigated agricultural operations. The long term infrastructure measure is the development of sources of recycled water in cooperation with the City of San Luis Obispo.

A strategic approach was implemented to meet these goals involving all effected stakeholders in the planning process and within the three main operational areas a variety of suggested retrofits, upgrades, and improvements were implemented.

While water reduction efforts are ongoing across campus, the projects that have been implemented as of December 2015 have already resulted in a reduction to ALL water uses by 31%, surpassing the Governors 25% potable water use reduction mandate. This effort has saved 141,419,521 gallons and has generating over $500,000 in water and sewer utility costs savings compared to the 2013 baseline.

Back to top

Waste Water

All waste water from the Cal Poly campus is discharged to the City of San Luis Obispo's sewer collection and treatment system.  Cal Poly, in partnership with the City of SLO, has invested capital funds to purchase a capacity share of the City's waste water treatment plant, and therefore receives a discounted rate for waste water.  While most commercial sewer customers (in absence of a sewer flow meter) are billed for sewer use as a percentage of their domestic water use, Cal Poly's sewer usage is measured by a state of the art ultrasonic flow meter and flume, which is calibrated twice a year.  This ensures accuracy in billing and reporting, effluent sewage volumes and cost.  Ongoing conservation efforts, such as installation of ultra low flow plumbing fixtures, have resulted in significant reductions in sewer volumes in spite of campus growth. To view raw waste water tracking data, download the linked XLS file.

Back to top

Water Quality

Cal Poly's Water Quality Management Plan, approved by the Central Coast Regional Water Quality Control Board and implemented by the Environmental Health and Safety Department, is a voluntary and cooperative approach to water quality management and permit compliance. The program seeks to maintain and improve the quality of water passing through the campus by monitoring pollution in surface waters, groundwater, and the wastewater that leaves the campus through the sewer system for treatment.

Water in Stenner Creek is tested quarterly for fecal coliform, an indicator of bacterial contamination. Recent testing shows pollution levels in line with historic trends and within water quality standards. Monitoring wells around the campus are used to test the quality of the groundwater, identifying nitrate levels above and below the campus gradient. Historically, water entering the campus has been cleaner than that leaving the campus; however, recent measurements indicate that nitrate levels in water leaving campus are lower than those entering, and continue a downward trend.

Despite seasonal fluctuations, the groundwater has generally met minimum standards. Since summer 2011 when there was a spike in nitrate levels leaving campus, levels have declined significantly and are well under acceptable limits.

Cal Poly tests for a number of pollutants in sanitary wastewater. Starting in 2012, new standards were adopted for several of these materials. Pursuant to the new standards, some contaminants that the campus had been monitoring are no longer considered significant enough to warrant testing, while others were added to the array. In general, the campus has met applicable standards with no more than one or two annual exceedances on any of these metrics in the last four years of monthly testing. Biochemical oxygen demand (BOD), which had previously been a problem, has greatly improved from peak years, and zinc has essentially been eliminated from the waste stream, largely due to Custodial Services' Green Cleaning program.

In recent years, the Utilidor hot water distribution system has undergone several changes in order to improve the efficiency and effectiveness of the system. Improvements include replacement of aging piping and isolation valves to reduce the risk and frequency of leaks. In addition, the hot water system was converted to a silicate based corrosion control program, eliminating the potential for discharge of more commonly used treatment chemicals - nitrite or molybdenum - should a leak occur.

Cal Poly promotes and participates in the annual county-wide Creek Day cleanup events. These events are held across San Luis Obispo County and include cleanup locations at Cal Poly. Each September before the rainy season begins, volunteers from the campus community come together to pick up litter such as food wrappers, beverage containers, cigarettes and smoking-related materials that make up between 60-80% of the debris found in the annual cleanup. For more information about Creek Day, and how you can help please visit To view raw waste water tracking data, download the linked XLS file.

Back to top

Related Content