I Have Low Cold Water Pressure But Not Hot, What Would Cause This?

One reason why there might be a problem with the water pressure could be clogging in the pipe. This is observed if the pressure is pretty good on the instant when you first turn on the tap but falls off almost immediately to low pressure. If only cold water pressure is the problem for you, there might be a mineral clogging in your cold water pipe only. If the low pressure problem is just on one fixture, you can trace the problem to a local issue to avoid more extensive plumbing surgery.

1. You first need to look under your sink(s) in bathroom and kitchen, adjust the valves by turning to get more or reduced pressure.
   
2. Remove by unscrewing the round part directly where the water exits on the faucet arm. Clean the screen with old toothbrush. Very common that small amount of rocks and sand have accumulated from rusting pipes and dirty water heater. 
   
3. There is clogging of rust into your pipes going to the cold water faucets and shower.