How to change a 2003 Honda CRV water pump?

You should purchase a repair manual. Autozone should have one in stock. Just read up on the water pump remove/replace section.

I think it will probably say something like

Raise the vehicle and support it on jack stands. Remove the wheel (on the side of the vehicle where the belts are)

It is a really good idea to replace water pump and timing belt at the same time. If you don't know how to replace a timing belt... you may be better off paying a mechanic. When you take the timing belt off, there is no room for error. You can't be off by one cog or else the job will have to be done over.

But if you insist on doing this job, you'll want to start will the engine at top dead center number one piston on compression stroke. If you are already lost. Stop and take your car to a mechanic. If you are still with me - drain the coolant and start taking the drive belt(s) off, you know - power steering, alternator, air conditioner, etc. Once these are out of the way, you can start taking off brackets that are in the way. You'll probably have to support the engine with a jack while you take the engine mount out of the way. If this all sounds hard, it is. But you haven't gotten to the really hard part yet. You have to make sure that the cam or cams don't move after you take the timing belt off. You'll need to mark the position of the crankshaft and cam or cams if you have dual over head cams. if you do have dual overhead cams, this makes it even tougher. Because they have to be perfectly positioned so that the crank and both cams are at top dead center compression stroke number one piston.