The City of Chicago wants residents on the South and West sides to sign up for lead water testing.
The Department of Water Management sent 280 letters to people who live on streets where water main replacement construction will take place in September.
Department commissioner Barrett Murphy says they want to test the water before and after the construction to see whether water main construction has any effect on the levels of lead in the water.
Workers will take four 1 liter samples at each site. Murphy says results could be ready in a month.