We are well aware of this situation. You've found a really good deal on a new kitchen faucet that can replace the old leaky faucet you already have. Once you get home, you excitedly start tearing down the old one and realize you can't loosen the big nut on the bottom of the faucet. Neither your monkey wrench nor any other wrench seems to fit in the space. do not be afraid. We'll show you how to remove and tighten an under-sink kitchen faucet nut.
Step 1: Clear the space under the sink
First things first – clean up the area under the sink. You need to be able to see the area where the sink faucet nuts are. You really can't do that unless you can get there and work. Remove towels, detergent, etc. Also consider throwing a nice towel over your head and shoulders so you can look up at the sink.
Step 2: Get Some Lighting
In addition to some safety glasses, bring a headlamp or other light so you can see what you're doing. You can have the best tool in the world, but if you can't see it – you can't use it! We like something similar to Milwaukee's line of LED headlights, but really, anything will do.
You'll need a tool called a basin wrench . These special plumbing tools have a long handle with a tee on one end so you can use leverage. The other end has a spring-loaded adjustable wrench head that clips onto the nut. The long handle allows you to reach behind the sink and reach those hard-to-reach nuts. You can buy a simple basin wrench for around $15 at most hardware stores or online.

A good example is the Ridgid Telescopic Basin Wrench. There are fancier and more expensive versions around, but for this once-in-a-lifetime job, a cheap wrench will do just fine.
Step 4: Use Your Wrist!
Once the tool is in place, a simple turn of the wrist provides enough force to loosen most nuts. The two types of nuts you'll come across are the retaining nuts for water supply lines and the plastic nuts for holding faucets in place. Any Basin wrench should work with one or both.
If you notice, some pot wrenches wrap around the supply line, while others offer a T-handle method. You have to decide which method is best for you.
