That list is published. The City of Hollister Building Division's Water Heater Requirements handout sets out what the inspector looks for. Knowing it before the job starts is the easiest way to avoid a failed inspection and a second visit.
Installation Versus Replacement
A replacement puts a similar unit where the old one stood, on the same gas line, vent and water connections. An installation changes something:
- a new home, addition or accessory dwelling unit getting its first water heater
- moving the heater out of a closet, attic or living space
- switching from a tank to a tankless unit
- adding a second heater for a large household
Each of these can change the gas supply, venting route, water piping, combustion air or drain line. That is why they take more planning than a swap. If your heater has failed and you simply want it replaced, see our water heater replacement page instead.
What the Hollister Inspector Checks
The city's handout lists twelve items. The ones that most often shape an installation are these:
Elevation in a garage. Gas water heaters in a garage must have their burners and ignition at least 18 inches above the floor, unless the unit is listed as flammable vapor ignition resistant.
Seismic strapping. Two straps, one in the upper third and one in the lower third, wrapped fully around the heater and secured to the wall. Plumbing tape is not allowed. Our earthquake strapping guide covers this in detail.
Venting. Vent sections need a minimum rise of 1/4 inch per foot, set clearances to anything combustible, and a termination at least 12 inches above the roof and 4 feet from any opening into the building.
Relief valve drain. Storage heaters need a listed temperature and pressure relief valve and a drain line of at least 3/4 inch, run to the outside and ending 6 to 24 inches above the ground, pointing down.
Gas connection. A shut-off valve next to the heater, and a flexible connector no longer than 3 feet.
Combustion air, bonding of the water and gas piping, and in some locations a protective bollard where a car could hit the unit.
Planning a Tankless Conversion
Tankless units heat water only when a tap is open, and they burn far more gas while running than a tank burner does. A gas line sized for a 40-gallon tank is often too small for a tankless unit, so the conversion may mean a new gas run from the meter.
Tankless heaters also use different venting from a standard tank, so the old vent usually cannot be reused as it is. Some are mounted outdoors, which changes both the venting and where the water lines run.
Sizing matters more than with a tank. A tankless heater is chosen for the flow it must supply at once, not for storage. We work that out from the fixtures you actually run at the same time before recommending a unit.
Relocating a Water Heater
Moving a heater out of a hall closet or attic into the garage frees up space and makes future service easier, but it brings in the garage rules above. That means elevation, strapping, a vehicle bollard where needed, and a new relief drain route to the outside. The water lines get longer too, so we look at whether a recirculation loop is worth adding so hot water still reaches the far bathroom quickly.
Outside Hollister
Gilroy, Morgan Hill, Salinas, Watsonville and San Benito County each run their own building departments. The underlying California Plumbing Code is the same, but permit processes and local handouts differ. We check the jurisdiction before quoting, including for projects in Gilroy and Morgan Hill.
Getting It Done Once
The cheapest installation is the one that passes the first inspection. That comes from planning the gas, vent and drain before the unit arrives, not after.
DAE Plumbing handles water heater installation for new builds, additions, relocations and tankless conversions across Hollister and the Central Coast, with the permit coordinated. We are licensed and insured, CA Lic. #1047507, and estimates are free.
Call (831) 801-1079, or (408) 728-2856 for Gilroy, Morgan Hill and San Jose.