1. Identify the area that is leaking.
A. Leaking from under the handle?
a. Replace Ball Assembly #1 in the diagram - Repair Part Delta RP70 for a lever handle faucet or Delta RP212 for knob style handles.
b. Replace Cam & Packing (#2 in diagram - Repair Kit Delta RP61). For faucets before 2007, use Delta RP1050 and RP61.
B. Leaking from the aerator?
a. Replace seats and springs (#3 in diagram - Repair part Delta RP4993).
a1. still leaking?
b. Replace Ball Assembly (#1 in diagram - Repair Part Delta RP70 for lever handles or Delta RP212 for knob handles).
C. Leaking from the Spout?
a. since the water travels through the hose and not the spout itself, a leak from the base of the spout would be unlikely. If this does occur, check the connection of the hose to the spray head. If the connection is not leaking, then check the hose for damage. Replace the hose if damaged.
The information is from Delta Faucet® if you have further questions about Delta Faucets call 1-800-345-3358.