Had a plumber replace washer assembly (Delta RP4993) on the hot water side. It was good afterwards for about 2 weeks, now it's dripping again - not as much as before, but it shouldn't drip at all. Why would it do that? Is there a way to tell if it's the hot side again or a new problem on the cold side (I have no plumbing tools) ?

Shut off the hot water shut off under the sink... if the faucet stops dripping then issue is with the hot water side, right? Post back with the result and we can better advise after that, OK?

Mark

Is it a shower faucet or a sink faucet?

The Delta RP4993 shows like a sink faucet if so do as mark Suggested, good luck.

John

Always replace both washers, hot and cold.
If it is Delta shower faucet than replace both springs, as well

Milo