CHICAGO — Officials are asking Chicago residents to limit their use of water amid significant storms this week.

An average of more than 3.8 inches of rain has fallen across Cook County since Saturday morning, according to the Metropolitan Water Reclamation District of Greater Chicago. More rain is expected on Thursday.

The district’s Tunnel and Reservoir Plan has 109 miles of tunnels and three reservoirs to deal with all that water — but it’s nearly at capacity, according to a news release. The part of that plan that serves the city and suburbs, the McCook System, is at full capacity with 5.1 billion gallons of water stored.

The mix of heavy rainfall and people’s continued use of water means there’s a risk sewer systems can overflow into Chicago’s rivers. Hoping to help, Friends of the Chicago River dubbed Wednesday an “Overflow Action Day” and called on locals to reduce the time they spend in the shower, turn off faucets and flush less, among other things, for the time being.

The Metropolitan Water Reclamation District also urged Chicagoans to “minimize their use of water before and during” storms.

Debra Shore, commissioner of the Metropolitan Water Reclamation District, said in a tweet she skipped showering on Wednesday — and urged others to “delay washing clothes, dishes, etc. while the system is at capacity.”

It's an #OverflowAction Day. Want to help? Reduce your water usage to lower the risk that our sewer systems would overflow into Chicago's rivers. It's as easy as holding off on laundry or shortening your shower. More tips from @chicagoriver: https://t.co/efh5Ncy0Xt. pic.twitter.com/VBBTSwBefn — MPC (@Metroplanners) May 1, 2019