Help. At campground. Bad smelling water

Does the water in the taps or toilet smell funky, too?  Have you sanitized the fresh water tank and plumbing lines?  Is there an odor from the P trap in the shower?  Are you hooked up to city water or are you using the fresh water tank?

The p traps may have been dry and it could be gases coming up from the tanks.  You can put some soapy water down the drains.  Turn on the exhaust fan.  If it was the p trap gas, the odor should go away.  Try that first.

Is the water discolored?  

Does the hot water faucet inthe sink have the same odor?

Take a cup of water outside and see if it still smells.

I wonder if the previous owner never emptied the Alde tank?  Even though they said they never used the hot water doesn’t mean the tank never filled.  The Alde tank does not get hot enough to kill the cooties that may be in the tank, I think the tank needs to be cleaned.  You need to contact Alde.  
Now If it were me, at a campground with full hook ups, I would disconnect from city water,  add a 1/4 cup of diluted bleach to your fresh water tank and fill it up with fresh water, run the pump and open all your taps to get bleach throughout the plumbing, then turn off the taps and pump and let the water sit for several hours.  I know technically you should not expose the Alde to bleach, but chances are a single exposure should not matter.  Check your pump filter to see if there is any debris and check periodically as you run the pump.  Then, empty and fill the fresh tank with water and flush the system until there is no further odor of bleach.

@Tea, Have you smelled the water coming from the city hydrant? Maybe the campground system needs to be flushed - it is early in the camping season? Do you have a filter on your city water hose?
Just some more possibilities!

If you turn on the Alde to heat the cabin, it will automatically heat water in the Alde tank.  If you don’t need cabin heat, but you want hot water available, just turn the thermostat down so the glycol does not circulate.  You will then have a ready supply of hot water.  In the summer, some folks just turn the Alde on an hour before they plan to need hot water.