Water running slow after new water heater installed, in kitchen both hot and cold running slow. Only hot running slow in bath room.

Remove the Aerators open the faucet see water flow if it is OK, clean the screens see the image below after cleaning install Aerators, if water doesn’t flow good problem is with the faucet may need to remove the cartridges, good luck.

John

water running slow after new water heater installed, in kitchen both hot and cold running slow. only hot running slow in bath room.
In replacing the WH you might have dislodged some minerals built up in the pip walls, If cleaning the aerators doesn't cure the problem you night have to start opening up valves and flushing lines. Let me know how it goes with the aerators. Good luck, Tom