I have dual sinks in my upstairs bathroom. The last week I've noticed that it will randomly fill up with water and then not drain. I recently manually emptied the sink. After washing some dishes in the kitchen sink downstairs, I noticed that the sinks upstairs filled up again. What could be causing this? What do I need to do fix this problem? Thanks in advance.

Is this a single dwelling or a condo/apartment? Back to you. Tom

It is a single family home.

Your lavatories(sinks are in the kitchen and) can't just fill up by themselves. There has to be a energy source to you in the new one every second someonepush the water up the lavatory drain pipe. There's something missing here, Can you fill in the blanks? Back to you, Tom

I am not sure what else I can add to explain. My upstairs guest bathroom sinks are starting to backup and then not drain. They start filling up with water (assuming backing up from the drain because we stopped using the faucet for at least a week) when other water sources in the home are used. Also, since there are two, when one is manually emptied (using a container to scoop out the water and dump in the tub) the other sink also drains. But then once water is used from another faucet it will rise up in these 2 bathroom sinks. Seems like whenever the kitchen faucet is used is when water comes up the drain in the upstairs bathroom.