Critical aquifer recharge areas

The goal of establishing critical aquifer recharge areas (CARA) is to protect a community’s drinking water by preventing pollution and maintaining supply. We help cities and counties comply with CARA requirements that are required by the state Growth Management Act.

Why does groundwater protection matter?

Washington residents get at least 60 percent of their drinking water from groundwater. Most people in rural areas get their drinking water from groundwater.

What is our role?

We provide technical assistance and review for counties and cities to help them protect groundwater. Cities and counties must identify where important groundwater resources are so they can protect their drinking water supply.

Protection of Critical Aquifer Recharge Areas is required under the Growth Management Act.

How to protect groundwater resources

The Growth Management Act defines CARAs as “areas with a critical recharging effect on aquifers used for potable water.” The following steps characterize where groundwater resources are important to understanding how to protect them.

  • Identify where groundwater resources are located.
  • Analyze the susceptibility of the natural setting where groundwater occurs.
  • Inventory existing potential sources of groundwater contamination.
  • Classify the how vulnerable the groundwater is to contamination events.
  • Designate areas that are most at risk to contamination events.
  • Protect groundwater by minimizing activities and conditions that pose contamination risks.
  • Ensure that contamination prevention plans and best management practices are followed.
  • Manage groundwater withdrawals and recharge impacts to:
    • Maintain availability for drinking water sources.
    • Maintain stream base flow from groundwater to support in-stream flows, especially for salmon-bearing streams.

We can provide technical assistance to local governments working to protect the functions and values of a community’s drinking water by preventing pollution and maintaining supply.

Our Critical Aquifer Recharge Areas Guidance Document helps you understand what is required for protecting local groundwater resources under the Growth Management Act.

Agricultural operations can help protect CARAs through the Voluntary Stewardship Program.