# Should You Repipe or Line Your Water Supply Pipes?

> Epoxy pipe lining vs repiping for water supply pipe: how each method works, where lining fits, its limits in old galvanized, and what to ask before choosing.

URL: https://philadelphiafreedomrepipe.com/guide/repipe-vs-pipe-lining/

Decision Guide

Epoxy lining coats the inside of the pipe you have; a repipe replaces it. What each method does, where lining can make sense, where its limits show up in old Philadelphia houses, and how to compare the two honestly.

Last Updated: October 26, 2026

**For most old Philadelphia houses with galvanized supply pipe, a repipe is usually the more certain fix, but lining is a real method with a place.** Epoxy lining cleans the inside of the existing pipe and coats it, which can seal small leaks and slow corrosion with fewer wall openings. It works best on pipe that is still structurally sound. It cannot restore pipe that has already lost too much wall, and it leaves the old layout, valves and material in place.

[Philadelphia Freedom Repipe](https://philadelphiafreedomrepipe.com/) replaces water supply piping and does not offer pipe lining, so read this as an explanation of both methods, not a sales pitch for either. The goal is to help you ask the right questions when a lining proposal and a [whole-house repiping](https://philadelphiafreedomrepipe.com/whole-house-repiping/) quote are sitting side by side.

## How epoxy pipe lining works

Lining a water supply system follows the same basic steps whichever product is used:

1. The system is shut off and drained, and the pipe is dried with heated air.
2. An abrasive is blown through the pipe with compressed air to scour off rust, scale and old deposits down to bare metal.
3. Epoxy is blown or pulled through the pipe so it coats the inside wall.
4. The coating cures for the time the manufacturer specifies, then the system is flushed, tested and returned to service.

The work is done from access points at the ends of each run, usually at the meter, the water heater and the fixtures, so walls along the length of a run do not need to be opened. That is the main attraction. In a tiled bathroom, a finished high-rise apartment or a house with fragile decorative plaster, fewer openings can matter a great deal.

## How a repipe works by comparison

A repipe takes the old supply piping out of service and replaces it with new pipe, usually PEX or copper in a Philadelphia house. New pipe can follow a new route, with shutoffs at each fixture group, a new main shutoff and the metallic section the Philadelphia code requires at the water heater. Openings are cut where fittings have to be reached, and the [plaster walls guide](https://philadelphiafreedomrepipe.com/guide/repiping-plaster-walls/) explains how they are kept few. The old pipe is removed where exposed or abandoned in the walls.

|  | Epoxy lining | Repipe |
| --- | --- | --- |
| What happens to the old pipe | Cleaned and coated, stays in service | Taken out of service, removed or abandoned |
| Wall openings | Fewer, at the ends of runs and at fixtures | More, at fittings, turns and fixtures |
| Layout and valves | Unchanged; valves are replaced, not lined | New layout, new shutoffs where planned |
| Works on thin or cracked pipe | No; the pipe has to be sound | Yes; the old pipe is no longer relied on |
| Material on record | Original material, coated | New material allowed by code for the building |
| Testing | Flush and pressure test after curing | Pressure test before walls close, flush after cutover |

## Where lining can make sense

Lining is worth a serious look when the pipe is mostly sound but has a corrosion problem on the inside: copper with scattered pinhole leaks, for example, where the wall elsewhere is still thick. It can also make sense where opening walls is unusually costly or disruptive, such as a building where finished surfaces are hard to match or where people cannot easily be moved. In those cases, coating the pipe can buy years at lower disruption.

Pinholes in copper have more than one possible cause, from water chemistry to velocity to how the original joints were made, and a lining does not change the cause. The [copper pinhole leaks guide](https://philadelphiafreedomrepipe.com/guide/copper-pinhole-leaks/) explains why, and why a pinhole in one place does not prove the whole system is failing.

## Where lining runs into limits in old Philadelphia houses

By Census figures, 39.9% of Philadelphia’s housing units were built in 1939 or earlier, and many of them still carry galvanized steel. Galvanized pipe raises three problems for lining:

- **Lost wall thickness.** Galvanized corrodes from the inside, and the threaded joints are the thinnest points because the threads cut into the wall. Blasting out decades of scale can expose pipe that is close to failing, and a coating does not add strength.
- **Small branches and fittings.** Short branches, tight elbows and old valves are hard to clean and coat evenly. Valves are replaced rather than lined, which means openings at those points anyway.
- **What sat on the pipe wall.** The Philadelphia Water Department notes that, over decades, lead from a property’s plumbing can collect on the corroded walls of galvanized pipe. Lining removes and covers that layer; a repipe takes the pipe out of service. Either way, the [guide to old water pipes in Philadelphia homes](https://philadelphiafreedomrepipe.com/guide/old-water-pipes-philadelphia-homes/) explains where lead can come from in older plumbing.

Lining also leaves the original layout. If the house has an undersized main, a seized [main shutoff](https://philadelphiafreedomrepipe.com/main-water-shutoff-replacement/) or a branch that cannot be isolated, those stay unless they are separately replaced. And lining does nothing for the service line from the street, which in Philadelphia is the owner’s and is a separate job covered on the [lead service line replacement](https://philadelphiafreedomrepipe.com/lead-service-line-replacement/) page.

## Permits, records and resale questions

In Philadelphia, L&I requires a permit for plumbing replacement and repair work other than minor same-material repairs and stopping a leak, overseen by a licensed master plumber. How L&I classifies a lining job is a question for L&I before work starts; a repipe goes through the plumbing permit described in the [Philadelphia repipe permit guide](https://philadelphiafreedomrepipe.com/guide/philadelphia-repipe-permit/). For later owners and inspectors, a repipe leaves a permit record naming new piping. A lined system is still the original pipe, so keep the product name, its certification and the installer’s paperwork.

## Comparing the two on price

No published Philadelphia price range was found for lining, and the site does not publish one. What moves either price is similar: the number of fixtures and floors, access, and restoration. Lining trades opening-and-patching work for cleaning and coating work. A repipe of a single-family house or rowhouse typically runs $4,000 to $15,000+ around Philadelphia, and the [repiping cost guide](https://philadelphiafreedomrepipe.com/guide/repiping-cost-philadelphia/) explains the drivers. Compare written scopes, not headline numbers: which runs are treated, which valves are replaced, what is tested and how, and what is guaranteed in writing by each installer.

## Questions to ask before choosing

- What is the pipe made of on every floor, and how thick is the wall at the joints?
- Which runs would be lined, and which valves and fittings replaced?
- What certified product is used, and what are its cure and testing steps?
- How many openings does each method need, and who closes them?
- Does either option change the layout, the shutoffs or the water heater connection?

If the answers point to sound pipe with a local problem, a [partial repipe](https://philadelphiafreedomrepipe.com/partial-repiping/) or lining may both be worth pricing. If they point to thin galvanized throughout, replacing it is usually the scope that stops the next failure.

## Questions about this guide

### Can epoxy lining fix galvanized pipe that is already clogged with scale?

Lining starts by blasting the scale out, so a clogged pipe can be cleaned and coated. The problem is what is left underneath: galvanized pipe that has corroded for decades has lost wall thickness, worst at the threaded joints. A coating can seal small pinholes, but it cannot restore steel that is thin enough to fail.

### Is epoxy lining safe for drinking water pipes?

Lining products sold for drinking water are certified to NSF/ANSI 61, the standard for materials in contact with potable water, and the installer should name the certified product. Safety also depends on the job: the pipe has to be cleaned and dried properly and the coating cured as the manufacturer specifies before the water is used.

### Does pipe lining avoid opening walls?

It usually needs fewer openings, because the coating is pushed through the existing pipe from access points at the ends of each run. It does not avoid all of them: fixture valves, meters and some fittings still have to be disconnected and reached, and parts that cannot be lined, such as valves, have to be replaced.

## Related service

### Whole-house repiping

Every hot and cold supply line from the main shutoff to the fixtures, replaced in the material the Philadelphia code allows for the building and pressure tested before the walls close.

## More guides

- Learn [What Old Water Pipes Are in Philadelphia Homes, and When Do They Need Replacing?](https://philadelphiafreedomrepipe.com/guide/old-water-pipes-philadelphia-homes/)A plain guide to the water pipes inside an older Philadelphia rowhouse or twin: how to tell lead, galvanized steel, copper and plastic apart, how each one fails, who owns which part, what the city's code and permits require, and how to decide between a repair, a partial repipe and a whole-house repipe.
- Learn [How Do You Repipe a House With Plaster Walls?](https://philadelphiafreedomrepipe.com/guide/repiping-plaster-walls/)Plaster on lath can be opened and closed cleanly if the openings are planned. Where the cuts go, how routing keeps them few, the three levels of patching, and what keeps the dust in one room.
- Decision Guide [What Causes Pinhole Leaks in Copper Pipe, and Should You Repair or Repipe?](https://philadelphiafreedomrepipe.com/guide/copper-pinhole-leaks/)Why copper water pipe develops pinholes, what Philadelphia's water does and does not explain, how to read the pattern of leaks, and how to decide between a spot repair, a partial repipe and a whole-house repipe.
- Cost Guide [How Much Does Repiping Cost in Philadelphia?](https://philadelphiafreedomrepipe.com/guide/repiping-cost-philadelphia/)Typical ranges for a whole-house and a PEX repipe, what sits inside the price, the City's permit fees, and why two quotes for the same rowhouse can differ.
- Learn [Does Repiping Include Drain Pipes?](https://philadelphiafreedomrepipe.com/guide/does-repiping-include-drains/)A repipe replaces the pressurized pipe that brings water to your fixtures. The pipes that carry it away are a different system, built and repaired by different rules. Where the line falls, and why it matters on a quote.