This is a very quick and simple solution, and I mainly used materials I already had on hand. However, I think it provides a great baseline for you to create your customized version of a garden workbench & sink.
Step 1: Materials and Tools
plywood (mine is 28" x 36" and Made in Texas)
2x4's (mine are 4 x 28", 4 x 33", 4 x 38" and Made in Texas)
@ 30 x 3.5" deck screws
@ 30 x 1.5 deck screws
1 x bucket
1 x faucet
1 x 'Y' split hose adapter
1 x 1/2" hose coupling (part no.: Watts A-810)
1 x 3/4" / 1/2" Hose adapter (part no. Watts A-677)
1 x garden hose (length depends on your environment)
thread seal tape
Step 2: Frames
If you cut different sizes (or even to double check the layout) I recommend placing the 2 x 4's on top of the cut plywood to ensure that you have the boards lined correctly. On my bench, the 28" board is on the sides and the 33" are on the inside of the 28".
Step 3: Legs
NOTE - plywood shown in picture is not yet attached, only being used as a guide here.
Step 4: Top
Next, drill a 1" hole where you want the faucet to be located. I choose a corner to maximize the workbench space. Then, cut a hole for your 'basin'.
Step 5: Bottom Frame
Step 6: Faucet
Step 7: Don't Forget the Bucket!
After you decide on where to place your bench, add your 'Y' hose splitter to your spigot and connect the garden hose to one end of the "y" and your new sink.