Disinfecting Hard Household Surfaces After the Flood

QUESTION: How can I disinfect hard surfaces in my home that have been in contact with sewage-contaminated floodwaters?

ANSWER: Try sodium hypochlorite -- liquid chlorine bleach. Chemists from Ames Laboratory at Iowa State University suggest using a 10 percent liquid chlorine bleach and water solution. That translates into one cup of household bleach to nine cups of water -- or about one and one-half cups of bleach per gallon of water. The chemists say that using a 10 percent bleach and water solution is necessary to disinfect hard surfaces that have been contaminated with floodwaters containing sewage. (Note: be aware that the Iowa Department of health recommends one-half cup of bleach per gallon of water.)

QUESTION: Can I disinfect hard household surfaces with rock salt?

ANSWER: Yes. Use one cup of rock salt per gallon of water. But don't use rock salt on concrete. It will ruin concrete, causing it to chip, fragment, and flake. You can use rock salt on dry wall, and also on plaster -- but be sure to rinse the surface well afterward.

QUESTION: How important is rinsing?

ANSWER: Rinsing is very important. Always rinse afer you use bleach or rock salt. But be aware that in a flood situation, some sources of rinse water may be contaminated.

QUESTION: Can I disinfect hard surfaces using trisodium phosphate?

ANSWER: No. Trisodium phosphate is found in some cleansers. It cleans but it will not disinfect surfaces that have been contaminated by floodwaters.

ONE FINAL NOTE: NEVER MIX BLEACH AND AMMONIA! Hazardous fumes will result.