Answer: The stomach flu viruses can live on surfaces for about 2 weeks.
Once everyone in your house is done being sick, it is reasonable to assume that you will have stray viruses lingering on household surfaces for another 2 weeks. Norovirus has been shown to live on kitchen counter tops for at least 7 days1. They stopped testing after that so they probably live significantly longer. I am using the word “live” loosely since viruses are not technically alive. We really should say “remain infectious” in place of “live” and “destroy” in place of “die”. Rotavirus has been shown to live at least 10 days on a variety of surfaces. Adenovirus 40 was less stable and only remained for about 3 days2. Norovirus has been shown to remain in refrigerated food for weeks, and freezing is a great way to keep norovirus forever3. There was also an experiment done to test how long norovirus remained infections in ground water. It remained infectious for 2 months and then they stopped checking4.
My in-laws had a bad case of the stomach flu on December 18-19, 2009. They were well by December 20. They had relatives come visit for Christmas on December 26 (1 week later). 3 of the visitors came down with the same stomach flu starting about 36 hours after arriving. My in-laws never got sick again since it was the same virus they just had. So, 1 week is NOT long enough to wait. People and houses are still contagious! My family went to visit them 3.5 weeks later. (3.5 weeks after the last person vomited in their house). I was nervous and cleaned the bathrooms when no one was looking. My 2 year-old daughter had her thumb in her mouth the entire weekend we were there. Amazingly, we did not get sick. This is by no means conclusive scientific evidence, but it seems that waiting 3.5 weeks and cleaning the bathrooms is enough.
So if your family is sick, clean really well with chlorine bleach, Clorox Hydrogen Peroxide wipes, Lysol Disinfectant spray or some other product that claims to kill norovirus. Feel free to read my page dedicated to cleaning products that kill norovirus. Please be responsible and do not have company for 2 weeks after everyone is well. If you do have a guest, make sure you warn them of the risks and don't feel bad if they want to postpone their visit. I am sticking with my policy of not going to other people's houses until they have been well for 3 weeks after a stomach flu.
--Annie Pryor, Ph.D.