Working on 4 55gal drums in basement hooked through one of the water lines so it is always full and is recycled new every time you open the faucet.
Mark - Can 55 gallon drums hold up under your water supply pressure? They are kinda thin and I'd be worried about them eventually splitting at a seam. Non-functional 50 gal water heaters might be a more reliable option plus they already have the right fittings. Just a thought.