How long does the WH last?

I use the lowest flow and it extends the warm water capacity.

Looks like they are in for a sharp learning curve with RV showers. I've been there as we did most of our RVing with my DW and 3 DDs onboard. If we happened to be RVing where showers were provided they opted to use those in most cases and my son and I would hang back and use the rig's shower.

Since the kids are grown and too busy with college and work to accompany us on most trips it is not much of an issue. My DW showers first and I'll wait 10-15 minutes after before I get in. She never complains about running out of hot water and she has very long hair to wash and rinse.

We use the Oxygenics showerhead that uses less water while producing a more effective spraying action. Atwood also has a 10 gallon water heater which would at least be more productive for your situation. Regardless, showering in an RV means get in and get the job done.

dalenole.... excellent point! Holding tanks fill up very quick! When water starts backing up in the shower at their feet, you'll experience even MORE bone chilling screaming going on!

The other problem you will run into is the fresh water tank capacity. If you are not on full hookups or at least with water you will use up your water supply rather quickly.

If you are on a site with water available and do not have a sewer hookup then the grey water holding tank will be your limiting factor along with the fresh water availability.

Good luck with managing the water useage. Let them use the RV and you go to the campground shower. They then cannot blame you for using all the water.

Good luck and keep us informed.

Approximately 20 - 30 minutes to heat up from cold.

You can anticipate water at the shower to be about 50% hot and 50% cold to make it a comfortable body temperature. You can time the water, how many gallons per minute come from the shower faucet by simply catching the water in a bucket for 1 minute.

If your shower spits out 1 gallon a minute, that means you have used 1/2 gallon of hot water (at 50% and 50% hot and cold). (IF) the water remained at the steady temperature, you could take a 12 minute shower before all the water in the water heater is displaced with cold.

HOWEVER, as cold mixes with the hot in the heater, as the hot is being used up, cold will mix with the hot, making what once was hot begin to cool down.

The hottest water should always be at the top. The cold comes in from the bottom. But when cold and hot mix, well, it doesn't stay "HOT" very long. At best, you may get 3-4 gallons of truly hot water, after than, even the hot water begins to cool.

Recovery varies slightly, but mostly the same for all water heaters. Gas will usually recover faster than Electric, and if you run Gas and Electric at the same time, recovery is even faster.

Depending upon your shower head, it is possible to run water in the shower at a cooler temperature and the recovery in the water heater won't be so drastic.

Thus ... the reason everyone on these forums says, Learn to take Navy Showers!

Run water, get wet, get soap wet, turn water off.

Lather up (hair and all), put soap down, turn water back on and rinse.

Another thing, you will NOT be able to take showers back-to-back without some recovery.

Or, you can just let your wife and kids find out the hard way. After 6 minutes of a shower, it starts cooling down, and they turn the cold off, and the hot gets colder and colder, they WILL learn to take shorter showers!

Edit:
Practice the "Navy 3 minute shower at home". Time the wife and the kids. They might not like it, but if you don't, you'll really be paying for it in the camper!