Propane Houses and Tank Removal

Why this matters

On a natural gas conversion the utility owns the meter and has a process for pulling it. On a propane conversion the "utility" is a supply company that very often owns the tank in the yard, has a contract with the customer you have never seen, and may not hear about the conversion until a driver shows up to fill a tank nobody is using. Rural customers convert off propane for good reasons: they are usually paying more per unit of heat than gas customers, and they are paying for deliveries they have to schedule. But the job does not end when the furnace goes out, and the parts that remain (the tank, the yard line, the generator nobody mentioned) are where a propane conversion goes wrong.

This card covers the conversion-specific half: who controls the tank, what removal involves, what happens to the line, and how the propane appliances that stay change the arrangement. General propane system knowledge belongs to Propane Homes: What Every Trade Should Know.

If you smell gas at any point

Propane is heavier than air and collects low: basements, crawlspaces, window wells and trenches. If you smell it, get everyone out of the building, do not operate switches, lights, appliances or phones inside, and leave doors open on the way out. From outside and upwind, close the tank's service valve only if you can reach it without walking through the vapor, then call the propane supplier's emergency line and 911. Do not go back in until the supplier or the fire department clears it. Odorant can fade in a new tank or in soil, so a missing smell does not prove a missing leak; that is why a leak check is required before relighting anything on a system that was opened.

Who controls the tank

Leased or supplier-owned tanks. Across much of the US, residential above-ground tanks are owned by the supplier and leased or loaned to the customer, with the contract setting rental terms, minimum annual usage, delivery terms and what happens at termination. In these arrangements, the customer does not own the tank and cannot have it removed, moved or filled by another company. Several states also have statutes that limit filling a tank to its owner or someone the owner authorizes, which is the legal layer on top of the contract; check your own state's propane law.

Customer-owned tanks. Some customers bought their tank, often with the house. They can choose any licensed supplier, and at removal they arrange it themselves.

How to find out. Look for the supplier's name and a tank serial plate on the tank, then ask the customer for their contract or a recent delivery ticket. The answer decides who you call, and it is the first thing to settle on a propane conversion quote.

Who does what at removal

The rules for storing and handling propane come from NFPA 58, the Liquefied Petroleum Gas Code, in the edition your state adopts (usually through its fire code or a propane statute); it binds the supplier and any installer working on the system. In practice the work splits cleanly:

• The supplier handles everything from the tank to the first regulator: closing and locking the service valve, removing or pumping out remaining propane, disconnecting at the tank and hauling it away. An underground tank is either excavated and removed or, where local rules allow, abandoned in place after it is emptied and purged, which is the supplier's and the fire official's call.
• Your trade handles the house side: removing each converted appliance, capping each outlet, and testing the remaining piping. See related: How to Cap and Abandon a Gas Line Correctly.
• The customer gives notice under the contract. Many supplier contracts require written notice, set charges for pump-out or removal, and say whether unused propane is credited back, bought back at a stated rate, or forfeited. That last term surprises customers who just filled the tank in October.

Your shop's job is to make the customer aware of those terms before the install date, not to interpret their contract.

The yard line

The line from the tank to the house is usually customer-owned piping, often buried, running from the tank's first-stage regulator to a second-stage regulator at the house wall. When the tank leaves, that line is abandoned. Two points matter.

Cap both ends and say so. The supplier disconnects at the tank; the house end is capped at the second-stage regulator location or inside the wall penetration. Capped, emptied and tagged, an abandoned line is inert.

It will not be located later. The one-call 811 system marks utility-owned lines. A customer's private yard line is generally not marked by the utility locators, so a fence installer or a septic contractor digging three years later will not get a flag on it. Record its route on the customer's documentation and the job record. See related: How to Document a Converted House for the Next Tech.

When some propane appliances stay

This is where a propane conversion differs most from a gas one. With natural gas, keeping one appliance means a fixed monthly charge (see related: Keeping Gas for One Appliance). With propane, it means a tank sized and contracted for a different house.

Minimum use. A tank that used to take several deliveries a winter may now take one every year or two. Some leases carry a minimum annual purchase or a tank rental that applies below it. The customer should read their contract with that in mind.

A smaller tank or cylinders. A range alone can run on a pair of exchange or refill cylinders. A tank is filled to no more than about 80 percent of its water capacity, so a 500-gallon tank holds about 400 gallons, and a 100-lb cylinder, at about 4.24 lb per gallon, holds about 23.6 gallons. The appliance that decides between them is almost always the one with the largest burn rate.

The generator decides the tank. A standby generator on propane is a large intermittent load: it sits idle except for its weekly exercise cycle, then burns gallons per hour through an outage. Sizing the remaining storage for the range and forgetting the generator is the most common mistake on a propane conversion.

The remaining appliances still need their check. Removing appliances changes nothing about venting for the propane appliances that remain, unless they shared a vent with the furnace, in which case the venting consequence in What Removing a Gas Appliance Does to the Ones Left applies to propane the same way. CO alarms stay required where any fuel-burning appliance remains, under the IRC as adopted (R315 in the 2021 edition) and your state's law.

Worked example: the farmhouse with the generator

A farmhouse has a 500-gallon above-ground tank, leased from the local supplier, feeding a furnace, a water heater, a clothes dryer, a range and a standby generator. Delivery tickets for the last two years total about 1,700 gallons, so about 850 gallons a year. The conversion replaces the furnace, water heater and dryer with electric equipment. The range and generator stay on propane.

What stays. The tickets do not split usage by appliance, so estimate the remaining two from their ratings and the customer's habits. A range used daily takes a few dozen gallons a year; say 35. The generator's fuel chart (read from its manual; these figures are illustrative of the method) shows about 1.6 gallons per hour at half load. Weekly exercise of about 15 minutes is roughly 13 hours a year, about 21 gallons at the half-load rate; an exercise cycle usually runs unloaded and burns less, so that figure errs high, which is the safe direction for sizing storage. The customer reports one outage of about two days a year, 48 hours at 1.6, about 77 gallons. Total: 35 + 21 + 77, about 133 gallons a year, which is 133 of 850, about 16 percent of what the house used to burn.

Option 1, keep the 500. Its 400 gallons would last about three years at 133 a year. The lease's minimum-use term is the question; the customer calls the supplier.

Option 2, cylinders. Two 100-lb cylinders hold about 47 gallons. The range alone would take about 16 months to burn through that. One two-day outage at 1.6 gallons per hour takes 77, so the generator would run dry partway through the second day of its one expected outage.

Option 3, a smaller tank. A 120-gallon tank holds about 96 gallons at 80 percent. That covers the two-day outage at 77 gallons with room for the range, as long as it is filled before winter.

The customer chooses the smaller tank. The supplier swaps it, which is the supplier's work end to end. Your crew caps the three converted outlets, and the supplier performs its leak check on the remaining system before relighting the range and resetting the generator. The yard line stays in service for the new tank, so it is not abandoned.

What would have changed it. No generator, and two cylinders on the range would have been the answer, with the supplier removing the 500-gallon tank entirely and the yard line abandoned and recorded. A customer-owned tank, and the customer could have kept the 500, chosen any supplier, and avoided the lease question altogether. A three-day outage history, and even the 120-gallon tank would have been tight: 72 hours at 1.6 is about 115 gallons, more than the 96 it holds.

Where you stop

The tank, its valves, its regulators and the pump-out are the supplier's. The contract's terms, fees and credits are between the customer and the supplier, and questions about whether a term is enforceable belong with the customer's own attorney; this is not legal advice. Your part ends at a capped, tested, recorded house side and a customer who has called their supplier before the install date rather than after it.

References

• NFPA 58, Liquefied Petroleum Gas Code, in the edition your state adopts
• International Residential Code Section R315, 2021 edition as adopted, for CO alarms
• See related: Propane Homes: What Every Trade Should Know; The Propane Out-of-Gas Relight SOP; How to Cap and Abandon a Gas Line Correctly; Keeping Gas for One Appliance