I had to replace my double sink in the basement. Very old cast iron. The faucet was not attached to the sink so I was able to put in the new sink without replacing the faucet at that time. Now I want to replace with a new faucet which I will install on the sink… it has the 3 holes. My question… there is no shutoff valves going to this sink, so I assume I need to shutoff the water main where it comes in to the house. I will drain the water at the basement sink level. Will this affect my hot water heater in any way?  The water just drains out and then refills when I turn it back on?  Oh, I will be installing shutoff valves at this time!