Water Filter Woes

I finally found the water filter behind an access panel in the rear storage bay of our Jayco Greyhawk ME. It is very inconvenient as you have to lay on your side to remove it. I've tried to use the spanner wrench to unscrew the filter housing, but no luck. So I will probably end up having to take it to an RV dealer to have this simple thing done and spend $100 or more. Would it be better to have the RV mechanic do a bypass valve rather than pay to have him remove and install water filters once or twice a year. I understand you can put a water filter on your hose in place of a whole house filter. Thanks for your help.