Have been full timing for little over a year in stationary location with full hookups and in the last 3 weeks when first open faucet (cold) we get hot water out of the line. The water is even hotter that hot water side or at least as hot. The duration may be as long as 1 or 2 minutes. My water supply line is covered and insulated and 40 foot of it is under the unit out of the sun with only about 12-14 foot outside of trailer boundaries. I know there will be some heating of the water in the line and would expect that. This even happens first thing in the morning and nite temps are in hi 70's low 80's and toilet is used during the night so would expect "new" supply in line about dark thirty, which would alleviate super hot water in early morning. I estimated capacity of the supply hose at approximate a half gallon. That should dissipate within 20 or 30 seconds. We have been over 90 degrees since middle of may and over 100 degrees over 1/2 that time with no problem before three weeks ago. Can i have a problem with the water heater itself. Any help or suggestion appreciated.