Suddenly yesterday evening, the majority of cold water faucets throughout the house would turn to a trickle after being on a few seconds. The kitchen faucet did this too, but after a few minutes, it started operating normally again except for one slight trickle period the following day. All toilets tanks refill very slowly.

The master bath tub (2nd floor), basement bathroom shower and sink, and outdoor hoses (one at each end of the house) all operate at full power.

The oddest occurrence is the basement bathroom when the shower and sink operate normally but the toilet that is between these two systems refills Very Slowly.

The hot water faucets all operate normally at full pressure.

What would cause the loss of pressure on so many faucets at one time but leave others operating normally? Could there be air in the system? If so how would air get in? The house is 10-yrs old and it is summer time (no frozen pipes).