Adding a Gas Line for a Grill, Fire Pit or Pool Heater
The mistake is treating the new appliance in isolation. Every BTU you add draws on a supply that was sized before any of it existed.
July 10, 2026 · 6 min read
Outdoor living has been the growth area in North Texas home improvement for years — built-in grills, side burners, fire pits, pool heaters, patio heaters, and increasingly standby generators. Almost all of them run on gas, and almost all of them get added to a gas system that was sized before any of them existed.
That is the part that gets skipped, and it is the part that causes the problems nobody can explain afterward.
Why sizing is a whole-house question
Your gas system was designed to deliver a certain total volume, based on the appliances the house had when it was built — typically a furnace, a water heater, maybe a range and a dryer. The meter, the main line and each branch were sized against that demand.
Add a built-in grill and a fire feature and you have increased peak demand substantially. If the existing supply cannot deliver it, what happens is not a dramatic failure. It is a set of quiet symptoms:
- The grill produces less heat than it should, and nobody can work out why.
- The furnace or water heater underperforms when the outdoor appliances are running.
- A tankless water heater faults out — these are particularly sensitive, because they draw a very large amount of gas at peak.
- Burner flames go yellow or lazy on one or more appliances, which is incomplete combustion and a carbon monoxide concern on any vented appliance.
The symptoms show up on the appliances that were already there, which is why nobody connects them to the new patio.
What a proper job involves
Total the demand
Every gas appliance has a BTU rating on its data plate. The calculation adds up what can realistically run simultaneously, then checks whether the meter, the main line and the branch route can deliver it at adequate pressure over the distance involved.
Distance matters as much as diameter — pressure drops along a run, and an outdoor kitchen at the far corner of a property is a very different calculation from a grill on a patio next to the meter.
Establish whether the meter can carry it
Sometimes the answer is that the supply itself needs upgrading, which involves the gas utility. Better to find that out at the planning stage than after the patio is poured.
Route and material
Buried runs need appropriate material and depth, with tracer wire so the line can be located later. Exterior above-ground sections need protection from physical damage and corrosion. Anything passing under a driveway or patio needs sleeving — because the alternative is breaking concrete for a future repair.
Plan the route before the hardscaping goes in. Retrofitting a gas line under a finished patio is expensive and entirely avoidable.
Shutoffs and connections
Each appliance needs an accessible shutoff valve. Outdoor appliances need connections rated for exterior use. Sediment traps where required.
Pressure test, permit, inspect
Every gas job gets a pressure test before it is called finished, and gas work is nearly always permitted in the cities we work across. The inspection is not paperwork — it is an independent check on a system where a mistake is a fire or asphyxiation hazard.
Appliance-specific notes
Built-in grills
Straightforward, and the most common request. The main decision is natural gas versus propane — natural gas means never refilling a tank, propane means flexibility on placement. If you are converting an appliance between fuels, it needs the correct conversion kit; the orifices are different sizes and running one on the wrong fuel is genuinely unsafe.
Fire pits and fire features
Straightforward mechanically, but worth being careful about controls and safety shutoffs, particularly on anything with an automatic ignition or a remote. Manufacturer requirements vary and they should be followed exactly.
Pool heaters
These draw a lot of gas — frequently more than the rest of the house combined. A pool heater is the single most likely addition to expose an undersized supply, and it should never be added without running the calculation.
Standby generators
Increasingly popular in this region since the winter grid events, and they have a substantial gas demand at full load. There is also an electrical side to the installation that has to be coordinated properly. Worth planning as a project rather than an add-on.
Tankless water heater conversions
Worth flagging here because the same sizing issue applies and it catches people out constantly. A tankless unit draws far more BTU at peak than the tank heater it replaced, and an undersized gas line means it never performs properly. This is the most common reason a tankless installation disappoints.
Plan it early
If you are designing an outdoor space, get the gas planning done before the concrete and the hardscaping. It costs nothing extra at that stage and it costs a great deal to add afterward.
We size the system for the whole house rather than just the new appliance, pull the permit, pressure test, and coordinate the inspection. Call (469) 338-5533.
Frequently asked
Can I run a gas line myself?
We would strongly advise against it, and in most jurisdictions gas work requires a licensed contractor and a permit. This is the category where a mistake is not a leak you mop up — it is a fire, an explosion or carbon monoxide. Beyond the safety argument, unpermitted gas work creates real problems at resale and can complicate an insurance claim.
Natural gas or propane for an outdoor kitchen?
If you already have natural gas service, running a line is usually the better long-term choice — no tanks to swap, no running out mid-cook, and no storage. Propane makes sense where there is no natural gas service, where the appliance needs to be portable, or where the run to the location would be impractical. Appliances are generally available for either, but they are not interchangeable without a proper conversion kit.
How do I know if my gas line is big enough?
It has to be calculated rather than estimated — total connected load, what can run simultaneously, pipe diameter, and the length of each run. A quick indicator that you already have a problem: if existing appliances underperform when something else is running, or if any burner flame is yellow rather than blue, the supply is likely already stretched.
Why does my grill produce less heat than it should?
On a natural gas grill, inadequate supply is a common cause — either an undersized line, too long a run, or total household demand exceeding what the system can deliver. Other possibilities are a partially blocked orifice, a regulator problem, or a conversion done without the correct kit. It is diagnosable with a pressure test at the appliance.