Skip to main content

Water Sources & Users

Unlike other areas of California that receive imported water from the Sierra Nevada mountains via the state aqueducts, our water is entirely local. No water is imported from outside the region. Approximately 92,000 people and a diverse natural ecosystem of plants and animals rely on the Basin. Of these 92,000 residents:
  • About 80,500 residents (88%) receive water from a public agency – either from Soquel Creek Water District, Central Water District or the City of Santa Cruz.
  • About 11,500 residents receive water from private wells or from a small water system. California defines a “small” system as one that serves < 200 customer connections. There are 19 small systems in the Basin.
  • About 50,000 Basin residents (54%) rely entirely upon groundwater for their water supply. Soquel Creek Water District and Central Water District rely exclusively on groundwater, while the City of Santa Cruz relies on both surface water and groundwater.
  • About 42,000 residents within the Basin receive water from the City of Santa Cruz Water Department. In years with average rainfall, the City’s water supply is 95% from surface water and 5% groundwater. In a dry year, such as 2021, the City’s supply from groundwater for its customers within the Basin approaches 20%.
  • The average groundwater extracted from the Basin in the 5-year period from 2020 through 2024  was about 5,100 acre-feet. Approximately 76% was extracted by the 3 larger water systems , 12% was extracted by private domestic groundwater users , and the remaining 12% was extracted by a combined group of small water systems , agriculture, and other commercial users. The estimated safe level of groundwater extraction in the Basin is 4,870 acre-feet per year; this is referred to as the “sustainable yield” of the Basin.
The Santa Cruz Mid-County Basin Map
Click for larger image

Groundwater Use – 1980s to Present

From the 1980s into the early 2000s, more water was pumped out of the Basin than was naturally replenished with rainfall. Extractions remained high into the early 2000s, with over 8,000 acre-feet extracted in 2003. The over-extraction of groundwater led to a condition called “overdraft” which led to seawater intrusion into coastal aquifers. Long-term groundwater extraction in the Basin since 1985 in 5-year average intervals can be seen in the figure below.

In the past decade, the Basin tremendous progress towards reducing extraction to a more sustainable level. In addition to reducing groundwater extraction to combat seawater intrusion, Soquel Creek Water District is also shifting groundwater extraction inland by reducing groundwater pumping from coastal wells to inland wells – Figure X below shows the reduction in pumping within 1 mile of the coastline.  

For detailed annual water usage information, refer to Basin Annual Reports here.