Some sewers do contain messages--but not secret messages.
Groups of parents and kids use stencils to paint warning messages where water enters storm sewers. (They get permission from the city first.) These messages say things like “Dump No Waste--Drains to River.” They warn that if you dump gunk on the ground, it might end up in storm sewers, where it can travel to the river.
Some groups attach metal or plastic signs to the sewers instead of using paint. It’s faster to attach signs than it is to use paint. Also, the signs are often more colorful and have pictures of fish or crabs.
Girl Scouts help to put warnings on a storm drain. The warning says NOT to dump pollution in the storm drain. This drain carries rainwater to the Chesapeake Bay.
Photo: U.S. EPA
This plastic sign is put on storm drains as a warning. It says that if you dump pollution in the drain, it can travel to streams in the Four Mile Run Watershed.
Photo: U.S. EPA