The main factor is the cost of the water heater itself. The cost of labor is fairly standard dependent on area and contractor, but you will almost always pay more for rush service. Using the figures from HomeAdvisor.com, most homeowners spend between $666 – $1,099 for a newly installed water heater. The average being $881 based on over 9,000 respondents. The figures from HomeWyse are similar but in a smaller range. Depending on location, they say you should expect to spend $850 – $1,050.