What is the color code for hot water pipe line?

Typically there is no colour code. Any fresh water line running into your house is drinkable unless you have a reuse system. DON'T DRINK FROM IRRIGATION some citys use reclaimed water (grey water I.e. from showers and washing your hands) for irrigation.

ONLY Civilized countries use color codes

Countries with a bonifide plumbers guild and actually have a test for the masters licenses have color codes to prevent cross contamination of potable and non potable water systems.

Depending on which code one uses will dictate the color coding OR metal tags

stating safe water or Unsafe water. Round for safe triangle for Unsafe

The reason for color coding is in high rise building there is a variety of piping systems such as fire suppression , potable , gray water, Combined fire systems (stand pipe and sprinkler) Fuel - gas - oil - steam and industrial lines such as pneumatic lines for controls

The AWWA for example has under ground piping codes so in countries that have an established infrastructure workers know which piping are for utilities and waste and water supply rather then taking a chance of cutting into a wrong line