Daly City

Department of Water and Wastewater

153 Lake Merced Boulevard

Daly City, California  94015-1097

Phone: (650) 991-8200                               Fax: (650) 991-8220

Website

 

Service Area

 

The City of Daly City Department of Water and Wastewater serves the City of Daly City and some unincorporated portions of San Mateo County.

 

System

 

Profile

 

Area Size	7.4 square miles
Service Population	106,638
Number of Accounts	23,009
Number of SF RWS Connections	11
Connections To SF RWS Mains	Crystal Springs #1 and #2, San Andreas #2, and the Sunset Pipeline
Avg. Day Demand (mgd)	5.90
Avg. Day Purchases From SF RWS (mgd)	5.66
%  Demand Met With SF RWS Supplies	96%
Maximum Local Water Production (mgd)	3.43
Alternative Supply Sources	Local Groundwater, Recycled Water
Interties With Other Agencies	GVMID, Brisbane, Cal Water, North Coast CWD, and Westborough CWD
Local Storage (mg)	24.58
Days of Storage	3.37 - Length of storage based on loss of all sources of supply. Can meet the 8 hr criteria either separately or by pumping from zones with excess capacity. Well water, normally used as a supplemental supply, could meet partial demands in an emergency.

 

Summary

 

The City of Daly City is supplied by two sources of water: surface water from the SF RWS regional water system, local groundwater from five municipal wells in active operation, and a third source, recycled water produced by the North San Mateo County Sanitation District, a subsidiary of the City of Daly City, that provides turf irrigation to three local golf courses, an athletic field and landscape medians.
 

Daly City is connected to the SF RWS with eleven turnouts off the Crystal Springs #1 and #2, San Andreas #2 and Sunset Pipelines. Additionally, Daly City has emergency intertie supply connections with Guadalupe Valley Municipal Improvement District, Brisbane Water, California Water Service, North Coast County Water District and Westborough County Water District.

Blending of the SF RWS supply and local groundwater is required because a small portion of the well water exceeds the nitrate MCL. Blending the two supply sources reduces the overall nitrate concentration below the MCL while the well water acts as a buffer for corrosion control.

Daly City entered into a pilot conjunctive use aquifer recharge program in October 2002 with the SFPUC to promote the goal of enhancing regional water resource management. Daly City agreed to accept an increased amount of surplus SF RWS system water at a reduced rate and not pump groundwater from the Westside Basin. This action provided the opportunity to observe the response of the basin from recharge that takes place as a result of the reduction in groundwater pumping.

The Phase One demonstration project continued until November 2003 and assessed the feasibility of a proposed program to increase groundwater levels in the Westside Basin, reduce the potential for seawater intrusion, develop increased SF RWS system yield from the overall surface and groundwater system, and potentially improve conditions at Lake Merced. Initial results from the project showed that groundwater levels increased within the basin. The second phase of the aquifer recharge study began in March 2004 and continued until May 2007. A third phase began May 15, 2009 and ended in March 2011. Currently Daly City and the SFPUC are developing an agreement to implement a long term conjunctive use program based on the analysis of the pilot program.

The City’s distribution system includes 12 storage reservoirs, one of which is owned by a private entity, with a combined capacity of 24.58 million gallons that could, in an emergency, supply the annual average daily demand for just over 3.37 days. All reservoirs contain a mixture of SF RWS and groundwater, with the exception of Reservoirs #8 and #5 which are supplied solely by SF RWS connections. During this fiscal year, a two million gallon storage tank was constructed in the Bayshore Area to replace an undersized reservoir to enhance fire flows to the area. The system also contains 18 pumping stations, 23 pressure zones, 2 regulating control valves, 41 pressure-reducing valves, 21 pressure relief valves, 185 miles of main and 1,468 fire hydrants.

Daly City’s Tertiary Recycled Water Facility (through its subsidiary, the North San Mateo County Sanitation District) began delivering full Title 22 compliant public contact irrigation water in August 2004 to the Olympic Club. Soon after, water deliveries included the Lake Merced Golf Club and Daly City’s Westlake Park. During the 2005 irrigation season, deliveries included the San Francisco Golf Club. A study was conducted to examine the feasibility of adding service to Harding Park Golf Course. The study indicated the project was feasible, and construction is currently underway and is anticipated to be complete by the fall of 2012.

Since its initiation, some 2,386,590 ccf have been delivered for irrigation use, lessening the demand on local groundwater, and to a small degree, offsetting SF RWS system water with the conversion of potable water to recycled water at Harding Park.

 

Water Supply and Demand

 

Supply by Source	Actual FY 17-18 (ccf)	Actual FY 18-19 (ccf)	Actual FY 19-20 (ccf)	Actual FY 20-21 (ccf)
San Francisco Water	1,717,837	1,804,183	1,939,670	2,763,302
SF RWS Supplemental Water	1,060,963	1,055,309	1,057,033	0
Local Groundwater	0	0	0	0
Recycled Water	276,321	186,618	142,642	114,263
Total	3,055,121	3,046,110	3,139,345	2,877,565
mgd equivalent	6.26	6.24	6.43	5.90
Recycled water reflected in this table shows the amount of recycled water that offsets SF RWS water.
Demand by Sector
Residential	2,191,793	2,228,808	2,262,234	2,271,580
Commercial/Industrial	397,010	405,051	355,825	270,645
Other	36,395	25,502	26,541	69,456
Dedicated Irrigation	74,738	61,466	57,605	69,989
Non-Revenue Water	355,185	325,283	437,140	195,895
Total	3,055,121	3,046,110	3,139,345	2,877,565
mgd equivalent	6.26	6.24	6.43	5.90
Per Capita Use	Actual FY 17-18 (gpcpd)	Actual FY 18-19 (gpcpd)	Actual FY 19-20 (gpcpd)	Actual FY 20-21 (gpcpd)
Residential	41	42	43	44
Gross (Less Recycled Water)	52	51	57	53

 

Facilities and Distribution

Storage Reservoirs

 

Designation	Type	Capacity (gallons)		Designation	Type	Capacity (gallons)
Reservoir 1	Concrete	703,000		Reservoir 5B	Concrete	10,400,000
Reservoir 2	Concrete	2,303,000		Reservoir 6	Concrete	1,495,000
Reservoir 2B	Concrete	2,000,000		Reservoir 6B	Concrete	1,451,000
Reservoir 3	Concrete	978,000		Reservoir 7	Steel	1,487,000
Reservoir 4	Concrete	1,370,000		Reservoir 8	Steel	630,000
Reservoir 5	Concrete	1,481,000		F Bay (Private)	Steel	285,000
				Total		24,583,000

 

Wells

 

Name	Capacity (gpm)	Status
Westlake	410	Active
Well 4	426	Active
Jeff Well	340	Active
Vale	693	Active
A St.	524	Inactive
JS Well	550	Active
Total	2,943

 

Interties

 

Name	No.	Diameter (in.)
GVMID	1	12
Brisbane	2	8, 8
CWS	5	2, 4, 4, 8, 10
North Coast	2	6, 8
Westborough	1	12