Quick answerTankless water heater installation in Spokane usually means a wall-mounted gas unit, a gas line sized for its much higher input, new direct venting through the wall, isolation valves for annual descaling and a condensate drain on condensing models. A tank-to-tankless conversion typically takes a day. Hard aquifer water makes the descaling valves and a yearly flush essential.
Updated September 2026
Is tankless right for your house?
Tankless heaters suit households that run out of hot water with a tank, homes short on space, and anyone who wants the heater off the floor. They are not magic: flow is limited by the unit's size, so a small tankless unit can struggle to run two showers and a dishwasher at once in winter when the incoming water is cold. We size by the fixtures you run together and the coldest incoming water temperature, not by the number of bathrooms.
The bigger cost is usually infrastructure rather than the unit. Most tankless gas units need far more gas than a 40-gallon tank, so the gas line from the meter often has to be upsized.
What drives the cost of a tankless install
What every tankless install includes
What a tankless install involves
Tank to tankless conversions
We drain and remove the old tank, mount the tankless unit on the wall near the existing water lines, and repipe the hot and cold connections with isolation valves. The old tank's flue is capped or its chimney liner reused only if it serves another appliance, since tankless units vent separately. We set the output temperature, check the flow at your farthest fixture and explain the short wait for hot water, which is similar to a tank's but can feel different because the unit fires on demand.
Gas line and venting upgrades
A typical tank water heater uses a modest amount of gas; a whole-house tankless unit can need several times that when it fires at full rate. We calculate the load of every gas appliance on the line and resize the pipe from the meter where needed, which is the step that most often gets skipped and leaves a unit starving for gas. Tankless units vent through dedicated plastic or stainless pipe to the outside, placed away from windows, doors and the gas meter.
Descaling and annual flush
Scale is the main enemy of a tankless heat exchanger, and hard water builds it quickly. Every install gets a set of service valves so the unit can be flushed with a descaling solution and a small pump without disconnecting anything. We recommend a flush at least once a year on hard water, and we check the inlet filter screen at the same time. Skipping it shortens the unit's life and triggers error codes that look like a failing heater.
Tank or tankless
| Gas tank | Gas tankless | Electric tankless | |
|---|---|---|---|
| Runs out of hot water | Yes, when the tank empties | No, within its flow limit | No, within a lower flow limit |
| Space | Floor space for the tank | Wall-mounted | Wall-mounted, small |
| Gas line | Usually existing | Often upsized | None |
| Maintenance | Flush and anode checks | Yearly descaling | Yearly descaling |
| Best for | Lowest upfront cost | Larger households, long showers | Small homes, point of use |
Hard water in Spokane and the Valley
Most of Spokane County draws its water from the Spokane Valley-Rathdrum Prairie Aquifer, whose main dissolved minerals are calcium and bicarbonate, the ingredients of scale. Vera Water and Power, which serves part of Spokane Valley, reports its water runs from 12 to 18 grains of hardness per gallon. At those levels a tankless unit without service valves and a yearly flush will scale up long before its expected life.
How a tankless installation goes
- 1
Size by use
Fixtures run together and incoming water temperature.
- 2
Check gas and power
Gas load calculated, electrical checked.
- 3
Quote and permits
Written scope, permits filed.
- 4
Remove the tank
Drained, disconnected and hauled away.
- 5
Mount and pipe
Unit hung, water lines and service valves installed.
- 6
Gas and venting
Line upsized if needed, vent run and sealed.
- 7
Start-up
Gas pressure checked, flow tested, flush schedule explained.
Tankless water heater questions
Will a tankless heater run two showers at once?
A correctly sized gas unit usually will. Small or electric units may not in winter, when incoming water is coldest.
Why do I need a bigger gas line?
Tankless units burn much more gas at full rate than a tank. An undersized line starves the unit.
How often should it be descaled?
At least once a year on hard water.
How long do tankless heaters last?
Often longer than tanks when descaled regularly.
Can you install it where my old tank was?
Usually nearby, on a wall close to the existing water lines.
Other gas & water heating services we handle
Gas Fireplace Insert Installation
Sized, quoted and permitted.
Gas Fireplace Insert Installation detailsGas Fireplace Repair and Service
Answered 24/7, parts on the truck.
Gas Fireplace Repair and Service in SpokaneChimney Liner Installation
Sized, quoted and permitted.
How we handle chimney liner installationEndless hot water, installed properly.
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