I have a built-in oversized tub set into a tile-covered frame with a duel water controls to a single rectangular faucet that give the water a waterfall effec into the tub. Hot water pressure recently dropped to a trickle. All the other nearby outlets (sinks, showers) are fine. Can't get to the plumbing under the tub because of the frame design and the only valves along the way are at the hot water heater two floors down - they are open. I can't even get the fixture off the tub - I removed all five screws and nothing moves. Took the top off each water contril know and can't see anythere except the valve control and a locking ring. I fear a total tub rip-out to get to the root of the problem. Any ideas?

If one handle tap then , shut the water off to the tap at the hot water heater and dismantle the tap and pull the cartridge. Check the hot water inlet ports for any trash or debris that may be built up. Now I want you to place a pan over the open tap to prevent splash and turn on the hot water shut off valve, (or if you have shut the entire house down, turn on the water, count to thirty and turn it off). What you are doing is flushing the supply line and the open tap body. If the stream is good and the flow strong reassamble everything and see if your stream isn't better. One other thing that could cut down on the flow is a older piping system that is blocked with mineral buildup, such as rust built up in old galvanized pipes. However your case doesn't sound like that's the case. Good luck and thank you for rating my reply. Tom

The hot and cold water are separate taps. A problem I have is that I can't disassemble the taps or the spout. Then hot water went from full pressure coming out to nearly nothing over night.

I can't disassemble the taps ALL taps can be opened up. What's your problem? If two knobs, shut the water off to the hot side at the heater and dismatle the tap. Shine a light down in the open tap body and check the seat for any thing that may be blocking the flow. Now I want you to place a pan over the open tap to prevent splash and turn on the hot water shut off valve, (or if you have shut the entire house down, turn on the water, count to thirty and turn it off). What you are doing is flushing the supply line and the open tap body. If the stream is good and the flow strong reassamble everything and see if your stream isn't better. One other thing that could cut down on the flow is a older piping system that is blocked with mineral buildup, such as rust built up in old galvanized pipes. However your case doesn't sound like that's the case. Good luck and thank you for rating my reply. Tom