Last Friday at 2:45 pm PST I contacted Rheem tech support to order a replacement part for our water heater's control valve ... You can't buy replacement parts locally. They have to be purchased ...

Rheem manufactures water heaters for residential and commercial applications. The company offers a variety of gas, electric and tankless ... in for the replacement parts on Saturday morning ...

The Rheem RTEX-18 tankless water heater sells on Amazon for $422.61. That price is competitive with similar-sized tankless heaters and maybe a smidgen more than electric storage tank heaters.