Why Would My Gas Water Heater Have A Big Orange Flame?

Could be a dirty pilot. If it continues, it will soot and cause the main burner to burn yellow and plug up the flue. Dust, pet dander, spider webs, lack of combustion air (having water heater in a space that is too small to support enough combustion air). Call your gas supplier to clean.

You may have too much soot buildup around the burner. It would need to be removed and cleaned. Make sure there is enough fresh air feeding the water heater, also make sure there is enough gasline, if the gasline is overwhelmed then the whistling noise is the unit struggling for fuel. If it is just your pilot than clean it with a wire brush. There is a pilot adjusting screw on the controller that may allow for the pilot to be lowered.

The color of the flame is determined by the amount of oxygen its getting

If you are getting a whistling noise while only the pilot is in operation, The valving control might be breaking down. Pilot height is preset at factory. There is an adjustment, but the access is plugged from factory. You can use a steel pick to remove plug and lower the flame height or call a plumbing and heating professional to adjust it for you.

The color of the flame is dictated by the amount of oxygen mixed with the gas. It usually has to do with the orifice on the burner tube but there is usually a throttle if you will that you can adjust. It's really just a little flap of metal at the base of the burner.

I just had that problem. Took the vacuum cleaner, just used the Dyson without an attachment on the front suction tube, stuck it under the water heater and let it suck for about two minutes. Amazing amount of dust bunnies from underneath the heater (although we regularly vacuum the enclosure), and immediately, it burned blue again.

Underneath the pilot light is a small air vent .if not vented correctly the flame will (jump) and you will see the flame burning in the vent also. The pilot & vent needs cleaned.