DHCP Server Time

I have found that the DCHP server, which is run from a router is a day behind. It is giving lease times as a day behind. Will this cause problems? Where does the DHCP get its time from. I was told by the people who put it in, that I must have a server or computer with the wrong time, but I haven’t, after checking them all. They said that the router is set to the right date. Any Ideas.