So I did my own maintenance on my boat for the first time. When I drained the lower unit I found some water in it. I've never had a single problem and my last maintenance I had done on it there was never anything said about water in the lower unit. How concerned should I be?

Any water is too much.

Pat is right. Not good. Hopefully just a bad seal. You may not have any damage. Drain, refill replace seal. Check every time after using for awhile. Still have water, it's another problem.

Are you talking about the seals on the plugs?

Have your lower unit pressure tested... It could either be the prop shaft seals, shift shaft seals, drive shaft seals, or yes the gaskets on the fill or vent screw could be the cause... Either refill the lower unit and run it for a day and recheck for water or take it in for a pressure test... Lower unit ain't cheap... Dan

I'd R2 the fill and drain plug O-rings first. Run it on lake for at least 1 hour at several different RPM ranges and recheck for water. If found, drop lower unit and take it to shop for pressure test.

Thanks guys, I haven't hit anything that makes me worry but it is an 2001 motor so new seals maybe needed.

I’m it’s a 2001 it’s probably time for new seals on the lower unit either way.

We can take care of you

Discarded fishing line can get in the prop and cut a prop shaft seal that is one way water can get into a lower unit.
Take the prop off and have a look.

I second what Txbassin said about fishing line messing up a prop shaft seal and letting water in. Take your prop off look for fishing line behind the prop. Fishing line that has been on there for a while may look like a plastic ring because it gets hot and melts together. I had water in my lower unit and that is exactly what caused it. Prop shaft seals are cheap and easy to replace, so don't panic if the seal is broken or damaged. Glad you caught it before your lower unit locked up.