All delta faucets have spring-loaded washers that wear out with use
and hence need replacement. When you remove the handle, you will see
a (most-likely hand-tightened) nut which you need to unscrew to remove
the handle stem. Now you will see the spring-loaded washer which you
can fish out using a small screwdriver or the like. Replacement cost:
@ $3 for TWO washers (cold and hot sides). Make sure you turn off the
water before you embark on the project!