First: "WELCOME" to the wonderful world of RVing, and to the Forum where all the 'Experts' reside!
My City Water and/or Water Pump are always OFF if I'm not gong to be around for awhile, (pretty easy to flip a switch or turn a water faucet....not too easy to clean up a flooding...).
Also....I either have water supply via the Pump or via an outside source, (city water, etc.), but I can't employ both at the same time because of the plumbing configuration. As a coupla' others have already posted....I use a Pressure Regulator, (Watts 463A), and even if the Water Pump would/could run at the same time city water was flowing, it's not going to increase my water flow at the faucet and or shower.
Just my $.02....Enjoy the journey folks,
"HUTCH" '07 SILVERADO 3500HD 'CLASSIC' DRW - CC - 4 X 4
'07 NEW HORIZONS 35' 5th.Wheel 'MotoMover'
'06 HONDA 106hp.VTX1800 w/'HANNIGAN' Sidecar
"PRIMO" The Boxer
This is such a good site, everyone here is so smert!
I did learn something here tonight. Is it a good idea to have some water in your tank, then use your water pump for the toilet after you dump? All these years I've been filling up a bucket and dumping it in the toilet after I dump.
If using the fresh water tank, switch on the pump right before you use the water, then when finished, switch off the pump. Switches are cheap compared to water pumps.
Water pump sort of means dry camping. So if it's on there's a little on-light that's constantly drawing a little bit of your precious battery current....also, if you have any kind of leaky faucet, the pump is going to cycle every so often and make a little noise maybe in the middle of the night and in extreme circumstances- waste some of your precious water supply.
As to those who simply leave it on all the time- even when on city water and external electric- Basically there's no other harm done other than what folks have listed above- the pressure switch will keep the pump off, even though the system is on.....
So I won't fault them for leaving it on and forgetting it. If you keep some water in your tank- your system can be "totally automatic" where you "never" loose water when unhooking and moving.
Regarding the "flood warnings" they are a risk, but when hooked to external water- the flood risk is the same if not more)