When I turn the cold water in the bathroom sink on all the way, the pressure dorps about 50% after about 1/2 a second. If you open the valve slowly it is fine until you get about 3/4 open then the pressure drops. This is the only faucet that does it. Bathoroom renovation was done at some point in the house but I do not know when.

Not sure if this is a fixture or pipe problem.

Mattz

Sounds like an old Kohler shelf back compression faucet with the drop in seats. If they didn't get installed correctly you could get problems like that.

What type of faucet is it? Single handle or two handle? If it's two handle is it washerless, or does it have compression washers? If you can rotate the handle more than 3/4 turn then most likely it has compression washers and seats.

Next question. Are you comfortable taking it apart and putting it back together again? If you take a compression washer faucet apart, sometimes it isn't apparent how to put it back together unless you really paid attention to how you took it apart. (Don't ask how I know.) You also ought to know how it SHOULD look inside in order to notice if something is amiss. I would check for a loose washer or seat. (Might need a seat wrench or large allen wrench.)

Another possibility is a worn out supply connection between the shutoff valve under the sink and the faucet proper. I have seen them deteriorate internally until a chunk of rubber would flap off the side when the water was flowing and almost cut the flow off completely.

Start there and let us know what you find.

EPM

When we moved into this mobile home 8 yrs ago everything was fine with the water pressure. Everything was fine for the next 3-5 yrs actually. But starting with the washer the water pressure has sllowly started to decrease (only the cold water though). We took the water supply line off the washer and turned on the water to the house to flush the line. When we did chunks of white stone or crystals came out. Afterwards water pressure was better (not normal) but better. Then the problem moved to the master bath and we have had that problem in the master bath since (only master bath), but now recently cold water pressure has dramatically decreased in kitchen and spare bath also. We have flushed the lines several times and pressure only seems to get worse each time. We are at a severe trickle now. All sinks shower and washer. But the outside hoses all have great water pressure. I can't figure it out please help?:confused::confused: