Giving Doggie regular baths is important for more than hygiene. Dirty, greasy skin can cause itchiness and other issues. If you can't bathe Doggie regularly, you can't get rid of loose, dead hair. It will then end up on your couch, floor or bed. So what do you do if Doggie needs a bath but hates the water? You arm yourself with patience, and work on a step-by-step plan.
Make the "washing room" a nice place to be in. Some dogs are just as scared of the bathroom itself as they are of what happens there. You can heal the bathroom phobia by forgetting about bathing for a while. Instead, invite Doggie in when you're there, or call him so he follows you in, and then offer him a treat. Once he loses his fear if the bathroom, you can work on his fear of the bath itself.
Keep Doggie away from water when he's in the bathroom. Although that sounds like a contradiction, you want to make sure he trusts your reasons for inviting him in. Don't let him think you tricked him. So invite him in when you're taking a bath, but not while you're in the shower -- you might end up splashing him, and all trust will be lost.
Get him accustomed to water in a gentle way. For example, get a shower puff wet and let him smell it. Don't add shampoo or anything with a smell in it -- just plain water at first. Rub it once over his body, then let him smell it again. If he's okay with it, wet the puff again and repeat. If he goes crazy or gets upset about it, stop and try again the next day. Always let him smell the puff before you touch him with it -- that way he'll know there's nothing scary about it. You might need to do this for several weeks until he no longer worries about it when you approach him.
Use a bucket instead of the tap or the shower head when you're ready to try for a real bath. Some dogs are afraid of running water, so using a bucket will reduce the tension. To do this successfully, get two buckets and fill them with warm water. Add some shampoo to one and mix well until it feels soapy. Dip the puff into this bucket, and run it over Doggie a couple of times. Then use a small plastic bowl or cup to ladle clean water from the other bucket, and gently pour it over him to wash the soap away.