I noticed weak water flow at the kitchen sink and found the flexible supply lines from the shut off are smaller than 3/8 in. Is there a minimum requirement for a kitchen?

Jerome,
Low flow could have also been a result of a partially clogged screen (on the faucet), however lines are typcially 3/8". I would write it up as low flow and recommend further evaluation by a plumber.

Robert Dalga
Home Analysts
Kalamazoo, MI

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RJDalga
Home Analysts, Inc.
Kalamazoo, MI

Does the faucet start out strong and then go weak? If it does, you probably have a restriction in the main supply line. Place a pressure guage on the laundry hook-up, check the pressure. Now turn on another faucet and watch the pressure fall. Shut off that faucet and see how long it takes for the pressure to come back up. If it's slow, it's a restriction. I would start at the main valve or pressure regulator , if it's got one. (ok, let the plumber decide)

If it's slow all the time and other faucets in the home aren't check the aerator screen or there is "crap" (technical term) in the valve/head. We have very hard water out here in AZ. The aerator screens plug up frequently.

Good Luck with the Water Gods