I have unbelievable low pressure at my house. We're fed by a MUD and my neighbors don't seem to be having any issues. I don't have a leak (verified at the digital meter). When I first turn on a faucet I have seemingly ok pressure but then it slows down dramatically. I just tried giving my baby a bath and after 5 min I had 3 inches in the tub and the water was trickling out.

What do I need to check? I worked the valve at the street a couple times to make sure it was open. I have a water softener but I don't think that's the culprit because my sprinklers don't work either. I'm pretty handy and have no issue digging up my yard to avoid paying a plumber, just don't know where to start.

We have lived here 11 months and it would always drop when a toilet, sink, and hose were running, but the last 3-4 weeks it's gone to crap.

Weird update: back yard sprinklers have full pressure. The hose on the east side of the house and the sink in the garage have full pressure. The hoses in the back and west side don't work and nothing in the house works. How could half the sprinklers work and the other half not? I'm so confused.

Vacuum / air in the line?
Turn on all outlets for awhile and see if it blow out.

I don't think so. I think I have it narrowed down to the water softener.

Water comes into the house at NE corner and pressure is good at the hose. Next stop is my garage sink. Pressure is good on cold side but hot side is trash. Then the water softener and then the heater. It can't be the heater because the cold water in the house is bad along with the hot. That only leaves the pipe and the water softener. The pipe runs in my attic and I didn't notice any kinks in it.

Although if it were air in the line it could make sense because the pipe leaving the water softener goes vertical into the attic about 10'.

My water softener has a bypass and all is well! Is it worth trying to clean the water softener or should I just get a new one?