Hot Water Odor

Cleaning out the pipes with peroxide or soda and flushing the tank. It is an Atwood.
Another help possibly, is much of Florida's water supplies has a lot of sulfur.
You probably already use one though.
A small .5 micron or possible one not even that small will get the sulfur compounds. We have to change or clean the filter after a few days, because of the sulfur.

Another proven method to get rid of the smell, AFTER replacing the drain plug and/or anode rod, is to simply add an 89 cent bottle of hydrogen peroxide available at WalMart. Run it through and smell is gone. Won't hurt your pipes or you body....makes an excellent gargle too....good luck...Dennis

If it is an Atwood the following is from the service manual:

1. Turn off your main water supply. Drain your water
heater tank. Reinstall drain plug. Remove the
pressure-temperature relief valve. With a funnel
use 4 parts white vinegar to two parts water. (In a
6 gallon tank that would be 4 gallons vinegar to 2
gallons water).
2. Cycle the water heater, letting it run under normal
operation 4-5 times. At no time do you remove the
vinegar from the tank. Once this has been
completed, remove the drain plug and drain the
water heater.
3. After thoroughly draining the tank, to remove the
sediment, flush the water heater.
If you elect to use air pressure, it may be applied
either through the inlet or outlet on the rear of the
tank or applied through the pressure-temperature
relief valve. Remove the pressure-temperature
relief valve and insert your air pressure through
the pressure-temperature relief valve coupling. In
either case, with the drain valve open, the air
pressure will force the remaining water out of the
unit.
If air pressure is unavailable, your unit can be
flushed with fresh water. Fresh water should be
pumped into the tank either with the onboard
pump or external water pressure. External
pressure may be hosed into the unit either
through the inlet or outlet found on the rear of the
tank or the pressure-temperature relief valve
coupling located on the front of the unit.
Continue this flushing process for approximately
five minutes allowing ample time for the fresh
water to agitate the stagnant water on the
bottom of the tank and forcing the deposits
through the drain opening.
4. Upon completion of the steps above, replace the
drain plug and the pressure-temperature relief
valve.
5. Refill tank with fresh water that contains no
sulfur.

Some of the information above is water heater brand-specific. Since you don't mention what brand you have, I'll start from the top.

Turn off shore water and water pump. Open a faucet (hot) to relieve pressure.

Remove drain plug (Atwood) or Anode (Suburban).

Either flush out the bottom of the tank with a wand or use 6' of clear plastic hose to siphon precipitate from the bottom of the tank.

Install CORRECT DRAIN PLUG: Suburban- new or used ANODE with less than 50% erosion. Atwood- New Atwood nylon drain plug. With either, use 2 1/4 wraps of teflon tape to help seal and make it easier to remove next time.

Refill water heater. If smell persists, drain and use turkey baster, etc to add an ounce of bleach. Refill with water (open hot water faucet and let run until all air removed). Let sit for an hour. Drain and flush.

This is common. Drain and refill the water heater a few times and the smell will go away.

Is this just the hot water or all water in the coach. Are you in Florida or Mass?
If in Florida, run a cup of water from the faucet on the power pole and take a sip and smell. Lots of places in Florida have what is known as "Sulphur water" and it is just the nature of the water and not much can be done except to resort to bottled water (yuk) for drinking and cooking, or adapt to the Sulphur water as many Floidians have and actually enjoy it. The above mentioned remedies will help if it not Sulphur water. A suburban water will have the sacrificial anode rod that cause the water to taske bad when it needs replacing. If a Dometic water heater, they do not have an anode rod to blame, so multiple fills with mild bleach followed by a solution of baking soda will usually do the trick. Good luck with what ever route you take.

Change out the Anode, bleach again, should be good to go.......

Baking Soda...