I've been installing insulation under my house - there's a narrow crawlspace, so I'm sure I've knocked something about. When I got out, I had no cold water coming to our washing machine and the water pressure in the kitchen is extremely low. Here's the weird part, the hot water works in the washing machine and the the water pressure from the outside spicket is fine and it's on the same side of the house as the washer/kitchen sink. It's like something's pinching or something. Any clues?

speedball1

What kind of pipes do you have? Copper? Galvanized?
I can make a pretty good guess about what happened. When you were under the house you bumped against a cold water main and dislodged minerals that had built up 0n the pipe walls. The first fixtures to make a cold water draw sucked the crud up into the supplies and now are clogging them.
The crud has also got into your water heater and it must be flushed out.
Let's do the washer first. Shut off the cold water to the washer and remove the hose. Check and clean the screen in the hose and see if the washer fills now.
For the sink unscrew and remove the aerator on the end of the faucets spout. Same thing. Check and clean the screen. Replace and test. If that don't get it get back to me.
Unless you flush the crud out of the heater you'll find yourself with the same problem in the hot water side as you now have on the cold. Let me show you how.
For long life and fewer troubles you should keep your heater clear of mineral build-up by flushing on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run untill the water runs clear. You will see a spurt of red,(rust) followed by white grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures. Now pull each aerator and clean the screens. Be sure you put them back togather the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Good luck, Tom