We just installed a new hot water heater and there is no water flow to the bathroom sink at all, only cold water to the kitchen sink and no hot water to the washing machine. What should I do? The shower does work just fine.

Remove and clean aerator. Aerator is the removable attachment on tip of the faucet (spout). Washer has screens inside hoses and where hose attaches to the washer ( inside washer ). Clean them as well...

I agree with Milo, remove the Aerator clean the screen and install, see the image below, good luck.

John

I agree to a certain extent but " only cold water to the kitchen sink " tells me this aerator is clear and you still have no hot. I think you need to start clearing debris out of each hot inlet too.

We just installed a new hot water heater and there is no water flow to the bathroom sink at all, only cold water to the kitchen sink and no hot water to the washing machine. What should I do? The shower does work just fine.

Bob,

If you read the first few words OP says no water flow to the bathroom sink at all, this is why I suggested to remove the Aerator other wise I agree with you if the hot water flows good through a spout the Aerator is out of question, Thanks.

Resgards,
John

Correct John but "only cold water to the kitchen sink " tells me this aerator is clear. Problems at 3 or more faucets and at least one know clear aerator tells me to be looking at the valves more than the aerator. I would still clean all areators but to find still clogged even with aerators removed.