Coastside County Water District

Updated: July 20, 2022

766 Main Street

Half Moon Bay, California 94019-1995

Phone: (650) 726-4405 Fax: (650) 726-5245

Service Area

Coastside County Water District provides water to the City of Half Moon Bay and several unincorporated coastal communities in San Mateo County, including El Granada, Miramar, and Princeton by the Sea (Pillar Point Harbor).

System

Profile

Area Size	14 square miles
Service Population	18,789
Number of Accounts	7,604
Number of SF RWS Connections	2
Connections To SF RWS Mains	Upper Crystal Springs Intake and Pilarcitos Reservoir at Stone Dam
Avg. Day Demand (mgd)	1.82
Avg. Day Purchases From SF RWS (mgd)	1.45
% Demand Met With SF RWS Supplies	79.63%
Maximum Local Water Production (mgd)	0.5
Alternative Supply Sources	During a drought, local production is extremely low due to dependency on surface stream flows and a small watershed.
Interties With Other Agencies	None
Local Storage (mg)	8.0
Days of Storage	Approximately 3 days

Summary

Coastside County Water District has four water sources; (1) Pilarcitos Lake at Stone Dam, (2) Crystal Springs Reservoir, (3) the Pilarcitos Creek Infiltration Well Field, and (4) the Denniston (groundwater and surface water) Project. Water purchased from the SF RWS is supplied from two different raw water sources: Pilarcitos Lake at Stone Dam and Upper Crystal Springs Reservoir.

Raw water from Upper Crystal Springs Reservoir, Pilarcitos Lake at Stone Dam and the Pilarcitos Creek Infiltration Wells terminate at the Nunes Water Treatment Plant. Raw water from Denniston Creek and the Denniston Well Field terminate at the Denniston Water Treatment Plant.

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	464,037	547,861	496,627	705,680
Local Groundwater	29,278	10,508	12,272	12,099
Surface Water	408,890	314,412	382,259	168,436
Recycled Water	0	0	0	0
Total	902,206	872,781	891,158	886,215
mgd equivalent	1.85	1.79	1.83	1.82

Demand by Sector
Residential	464,899	446,167	486,477	499,242
Commercial/Industrial	46,566	48,065	46,340	41,741
Other	165,626	266,457	255,259	163,455
Dedicated Irrigation	136,865	41,335	48,645	144,202
Non-Revenue Water	88,250	70,757	54,437	37,575
Total	902,206	872,781	891,158	886,215
mgd equivalent	1.85	1.79	1.83	1.82

Per Capita Use	Actual FY 17-18 (gpcpd)	Actual FY 18-19 (gpcpd)	Actual FY 19-20 (gpcpd)	Actual FY 20-21 (gpcpd)
Residential	57	54	53	54
Gross	110	78	97	97

Facilities and Distribution

Treated Water Storage Reservoirs

Designation	Type	Capacity (mg)
Denniston	Steel	1.50
El Granada 1	Steel	0.20
El Granada 2	Steel	0.15
El Granada 3	Steel	0.25
Miramar	Steel	1.00
Carter Hill	Steel	0.40
Carter Hill	Steel	0.60
Carter Hill	Steel	1.50
Miramontes	Steel	0.40
Alves	Steel	2.00

Total		8.00

Surface Water Treatment Facilities

Designation	Capacity (mgd)
Nunes WTP	4.5
Denniston WTP	1.0
Total	5.5

Wells

Name	Capacity (gpm)*	Status
D1	25	Active
D2		Inactive
D3	37	Inactive
D4	35	Inactive
D5	35	Inactive
D9	45	Active
P1*	40	November 1-March 31
P2*		Inactive
P3**		Active
P3A*		Active
P4*	100	November 1-March 31 Standby
P4A*	200	November 1-March 31
P5*	65	November 1-March 31
Total		635

*Surface water infiltration wells