. >> reporter: denise norris is sleepless in silver spring. >> it's been uncomfortable. i woke up in the middle of the night, and just hot, sweaty. >> reporter: she lives in the charter house, an apartment building that houses seniors. it hasn't had air conditioning since yesterday. some residents try to stay cool in the lobby. >> 97 degrees outside. we're in an apartment with no air. >> i'm a diabetic, for one thing. and since i've been in this building three or four times i've been taken out of here because my sugar dropped low because it's so hot. >> reporter: arlington housing corporation manages the building. tonight an official admits crews accidentally turned off a water valve connected to the building's ac, causing the ac to malfunction. what is going on with the air conditioner? >> well, right now what we're doing, ahc is doing a major pipe realigning throughout the entire building. this has been going on all summer. and so what we are almost at the end of that project. >> reporter: this evening they set up temporary ac. >> we have been providing since yesterday