Use a mirror! Turn off pump, open tap and when there is no pressure get a mirror and loosen the supply line to the toilet. Good chance you need a new washer. Find a plumbing supply or big box store and get a new one using the old one as a guide. It should be only a hand tight fitting with a good washer..
2020 Keystone Cougar 22RBS, Ram 1500, two Jacks and plenty of time to roam!
The difference between genius and stupidity is that genius has its limits. A.E.
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