Stop Fighting With The Loose Kitchen Faucet
How many times have you wrestled with a loose faucet on top of your sink? It seems to happen most often with single handled faucets...as you lift the lever up to start to flow of water, the entire faucet moves to the point you almost have to hold the faucet body with one hand while to lift the lever with the other. That's not to say that is doesn't happen to faucets with separate hot and cold handles, they have their problems too.
Typically, the problem is that the nut holding the faucet to the sink is loose. You will have to crawl under the sink to access this area, but it's not difficult. Once under the sink you will see the water supply lines going up to the faucet. Look just beyond these and you will see how the faucet attaches to the sink. Some faucets have two nuts that hold the faucet to the sink, and some have one large nut that holds it down. Usually it's the faucets with the one large nut that causes the most problems.
Ideally, a basin wrench will fix this in a matter of seconds, but you can use whatever you have access to...pliers, or even a crescent wrench.
I've also seen a cheap sink as the cause. A cheap stainless steel sink (the really thin kind) will allow the faucet to move as you operate it. Although the faucet may be tight to the sink, the thin sink will flex to the point that it seems the faucet is loose, but its not.
For bathroom sink widespread faucets that have two handles, sometimes the handles feel loose. For these types of handles, if the nuts under the sink are tight, try using your hand and turning the handle body clockwise above the sink. That should tighten it up nicely; this also works for bathtub widespread faucets.
If you are tired of the old faucet, here is some information on how to replace a faucet.