IF you are going to use the 'City Water' for source then by all means USE a water pressure regulator
You want one that has a decent flow rate and can control pressure....3 gpm minimum and 45-50#
I prefer a WATTS adjustable .....as it can be rebuilt if needed
I use it at spigot with a 'wye' to control water thru potable hose for refilling fresh water tank and thru the other non-potable hose for general service
I also exclusively use on-board pump since 2008 when had a major leak while sleeping using the pressure regulator, regulator controlled pressure to 50# but city water ran for HOURS flooding 5th wheel.
$6000 plus and 2 weeks of headaches (we were FTng at the time)
NOPE.....not again
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31