# Copper Repiping in Chicago

> Copper repiping in Chicago and copper-only suburbs: which tube type goes where, soldered vs press vs push-fit joints, NSF 372 parts, supports. Get an estimate.

URL: https://chicagolakerepiping.com/copper-repiping/

Copper repiping replaces water supply piping in tube of the weight the design and local code call for, joined by an approved method and supported so it can move as it heats.

Last Updated: October 26, 2026

**K, L, M** The three copper tube weights Chicago's water distribution table lists, from heaviest wall to thinnest

**Press-connect** Allowed for copper water tube since Chicago's 2021 amendments, pressed with a tool the fitting maker certifies

**0.25%** Maximum weighted average lead content for drinking-water pipe, fittings and valves under NSF 372

**Type L** The minimum above grade in Evanston's code, and required above ground in Park Ridge's

Copper repiping in Chicago is less a choice among materials than the one the code leaves standing. [Chicago Lake Repiping](https://chicagolakerepiping.com/) manages copper repipes in Chicago houses, two-flats and small multi-unit buildings, and in suburbs whose codes call for copper or where an owner prefers it. Licensed and insured plumbing contractors do the work. With the material settled, the decisions that remain are real ones: which weight of tube goes where, how the joints are made, how the pipe is held and protected, and where the rigid runs can travel through a finished building.

Those decisions change the price, the number of wall openings and how the system behaves for decades. This page goes through each one. If the question is why PEX is off the table inside the city, the [guide to whether PEX is allowed in Chicago](https://chicagolakerepiping.com/guide/is-pex-allowed-in-chicago/) covers the code and its history; if the house is still steel, see [galvanized pipe replacement](https://chicagolakerepiping.com/galvanized-pipe-replacement/).

## What happens on the first visit

The visit starts at the meter and the main shutoff in the basement, because the main sets the size of everything downstream. From there it traces the existing piping on every floor. Copper from earlier repairs gets a close look: green crust at joints can mean flux left behind or a slow weep, and the colored stripe on the tube, where it is still readable, tells whether a previous plumber used Type L or Type M. Sound copper from a recent repair may be worth keeping and tying into; copper with a history of pinholes is not.

Static pressure is read at a hose bibb, and flow is compared at the lowest and highest fixtures with two taps running, so a restriction in the old piping can be told apart from low supply. Then comes the routing question that matters most for copper. Rigid tube runs straight and turns only at fittings. Every change of direction inside a finished wall is a place that has to be reached, so the walk-through maps open joists, stacked closets, chases and the backs of cabinets where turns can happen out of sight.

## Why Chicago repipes are copper

The Chicago Plumbing Code’s table of water distribution materials, Table 18-29-605.5, lists brass pipe, copper and copper-alloy pipe, copper tube in Types K, L and M, and galvanized steel. CPVC, polypropylene and PVDF appear only for secondary water in process applications. PEX has no entry, and the code requires new and replaced water supply pipe to be of the listed materials. Chicago’s 2021 amendments expanded PVC for drain, waste and vent piping in low- and mid-rise residential buildings, but did not add a plastic water pipe.

Homeowners report holding off on a repipe in the hope that the City will allow PEX. Nothing in the City’s recent code work points that way, and the City’s own permit records include a 2022 permit to “correct plumbing code violations” by replacing PEX piping with new copper. The [PEX vs copper guide](https://chicagolakerepiping.com/guide/pex-vs-copper-repipe/) compares the two where both are legal.

## Type K, L or M

The three types share an outside diameter at each size and differ in wall thickness. Type K has the heaviest wall, and Chicago’s code lists Type K copper, or ductile iron, for water service pipe, the buried line from the street. Type L is the middle weight. Type M is the thinnest of the three. Chicago’s distribution table lists all three for the inside of a building, so the choice falls to the design.

A thicker wall gives corrosion and abrasion more metal to work through and stands up better to handling in tight framing. A thinner wall costs less and weighs less. Where the pipe runs, how hot it gets, how fast water moves through it and the local code all bear on the choice, and no single weight is right for every run. Each type is marked with a colored stripe, green for K, blue for L and red for M, so the tube delivered to the job can be checked against the quote.

## Soldered, press-connect or push-fit

Since the 2021 amendments, Chicago allows copper water tube to be joined by soldering with lead-free solder and flux to NSF 61, brazing, mechanical and threaded joints, press-connect fittings pressed with a tool certified by the fitting maker, and push-fit fittings listed to ASSE 1061.

Soldering is the old standard. The tube and fitting are cleaned, fluxed and heated with a torch until solder flows into the joint. It needs an open flame at every joint, which matters inside the walls of an older building where the framing behind the plaster has been drying for a century. Press-connect fittings carry a sealing ring and are crimped onto the tube with a powered tool. There is no flame, and a joint takes seconds, which shortens the time walls stand open. The tool and jaw set have to be the ones the fitting maker certifies for that system. Some press systems are designed to leak visibly when a fitting has been left unpressed, so the pressure test finds a missed joint. Listed push-fit fittings grip the tube with a toothed ring and seal it with an O-ring; they suit a repair in a spot where neither a torch nor a press tool fits.

Workmanship is where joint failures start, whatever the method. Too much flux left inside a soldered joint keeps working on the copper after the job is done. A burr left on a cut end throws turbulence into the fitting and can wear the wall downstream. A press fitting slid on short of full depth seals poorly. These are installation defects, not material defects, and they are why the joints get flushed and pressure tested before anything is closed.

## Supports, expansion and protection

Copper needs to be held, but not pinned. Hangers go at the spacing the code and the fitting maker set, and where copper rests on steel straps or touches steel pipe, the contact is isolated or the hanger is copper-coated, because two metals touching set up the same galvanic corrosion the code guards against at a copper-to-galvanized joint. Hot lines grow in length as they heat and shrink as they cool. A long hot run strapped tight at both ends, or jammed through a snug hole in a joist, ticks and creaks as it moves and puts strain on the nearest fittings. Room to move at turns and through framing prevents that.

Chicago’s code requires new concealed water pipe and any pipe exposed to low temperatures to be protected from freezing, so runs near exterior walls, in unheated porches or over crawlspaces are insulated or rerouted. Where new pipe passes through existing openings in fire-rated walls or floors, Express Permit work has to be firestopped. Brass belongs in this system too: valves, adapters and the converter fittings that join copper to any steel that stays are brass, and every one that carries drinking water has to meet NSF 372, a weighted average lead content of 0.25% or less.

## Pinhole leaks and what copper does not promise

Copper is not immune to failure, and a repipe should not be sold as if it were. Pinhole leaks have more than one cause. Water chemistry can attack the inside wall. Water moving too fast through undersized or overworked lines can erode it, especially at elbows on the hot side. The workmanship defects above, flux and burrs, leave their own marks. No single cause explains every pinhole, and the [copper pinhole leak guide](https://chicagolakerepiping.com/guide/copper-pinhole-leaks/) covers how to read the pattern of leaks in an existing system.

Chicago’s treated Lake Michigan water works in copper’s favor: the City adds corrosion control that coats pipe interiors to limit lead and copper leaching. That lowers the odds of internal attack but does not remove every cause, which is why the sizing and joint practice matter as much as the metal.

## Copper outside the city

The copper rule is Chicago’s, and some suburbs share it. [Evanston](https://chicagolakerepiping.com/service-areas/evanston/)’s amended plumbing code lists copper for water distribution, with Type L as the minimum above grade, calls for Type K copper on the buried water service, and treats brass and galvanized as repair materials only. [Park Ridge](https://chicagolakerepiping.com/service-areas/park-ridge/)’s code bars CPVC, cross-linked polyethylene and polybutylene for water distribution and calls for Type L copper above ground. Those are what each code says, and the rule is confirmed for the address before work starts.

[Oak Park](https://chicagolakerepiping.com/service-areas/oak-park/) and [Skokie](https://chicagolakerepiping.com/service-areas/skokie/) follow the Illinois Plumbing Code, which lists PEX alongside copper. Owners there can choose, and [PEX repiping in the suburbs](https://chicagolakerepiping.com/pex-repiping/) covers that option. Copper costs more than PEX as material, and rigid runs can need more openings, so the decision turns on price, access and preference rather than on one material being better.

## Permit and price

Inside Chicago, an in-kind copper repipe of existing piping goes through the Express Permit Program at $150 per dwelling unit, with $150 more per unit when risers are replaced, and a City inspector checks the work. It has to be done by the Chicago-licensed plumbing contractor on the permit, or by an owner on a single-family home they occupy. Price follows scope: $5,000 to $15,000+ is a typical Chicago-area range for a single-family [whole-house repipe](https://chicagolakerepiping.com/whole-house-repiping/), and a [two-flat repipe](https://chicagolakerepiping.com/two-flat-repiping/) of the whole building runs $8,000 to $18,000+. The [Chicago repipe cost guide](https://chicagolakerepiping.com/guide/repiping-cost-chicago/) explains what moves those numbers, and the [plaster walls guide](https://chicagolakerepiping.com/guide/repiping-plaster-walls/) covers the openings rigid copper needs.

## What's included

- Copper tube of the type the design and local code call for, named on the quote
- Joints made by an approved method: lead-free solder, brazing, press-connect or listed push-fit
- Valves and adapters meeting NSF 372
- Hangers and supports at the spacing the code and fitting maker set, isolated from dissimilar metals
- Room for hot lines to expand at turns and where they pass through framing
- A brass converter or dielectric fitting wherever copper meets galvanized that stays
- Firestopping where new pipe passes existing openings, and insulation where pipe runs in cold spaces
- Pressure test before walls close, and a flush after cutover
- The City of Chicago or village permit and its inspection

## Three ways to join copper under Chicago's code

|  | Soldered (lead-free) | Press-connect | Push-fit |
| --- | --- | --- | --- |
| How the joint is made | Cleaned tube and fitting are fluxed, heated with a torch and filled with lead-free solder | A fitting with a sealing ring is slid on and crimped with a powered tool | The tube end is cut square, deburred and pushed into a listed fitting past its seal and grip ring |
| Heat in the wall | Open flame at every joint | No flame | No flame |
| What has to be right | Clean surfaces, the right amount of flux, full heat and flux residue flushed out | Full insertion depth and the jaw set and tool the fitting maker certifies | A square, clean cut and full insertion depth |
| Where it fits | Open basements and chases where heat can be managed | Inside finished walls with old, dry framing, and jobs that need to move quickly | Tight repairs where neither a torch nor a press tool fits |
| What to ask | Which solder and flux, and how fire risk is handled | Which fitting system and whether the installer's tool is certified for it | Where push-fit fittings are used and why |

## Related resources

- Decision Guide [Is PEX allowed in Chicago?](https://chicagolakerepiping.com/guide/is-pex-allowed-in-chicago/)Where PEX is and is not allowed: what Chicago's water distribution table actually lists, what the 2021 and Phase 3 code changes did and did not touch, which suburbs allow PEX, and what to do about plastic pipe already in the house.
- Decision Guide [PEX vs copper: which is better for a repipe around Chicago?](https://chicagolakerepiping.com/guide/pex-vs-copper-repipe/)Neither pipe wins everywhere. Where your address sits decides whether there is a choice at all, and where there is one, routing, joints, exposure and budget decide it.
- Learn [What causes pinhole leaks in copper pipe?](https://chicagolakerepiping.com/guide/copper-pinhole-leaks/)Why a sound-looking copper line can weep through a hole the size of a pin, what Chicago's treated Lake Michigan water does and does not explain, and how to tell a one-off from a pattern.
- Cost Guide [How much does it cost to repipe a house in Chicago?](https://chicagolakerepiping.com/guide/repiping-cost-chicago/)Typical ranges for a single-family house and a two-flat, what sits inside the price, the City's permit fees, and why two quotes for the same house can differ.
- Learn [How are plaster walls opened and patched during a repipe?](https://chicagolakerepiping.com/guide/repiping-plaster-walls/)How new supply pipe gets through a lath-and-plaster house, where the openings go and why, and how to read the restoration lines on a repipe quote so nothing is left to assumption.
- Learn [Do you need a permit to repipe a house in Chicago?](https://chicagolakerepiping.com/guide/chicago-repiping-permit/)What the Department of Buildings' Express permit covers when repiping a Chicago building, what pushes a job into plan review, the documents a riser or condo job needs, and what the suburbs do differently.

## How a repipe runs

1. First call What you are seeing, the building type, how many units and fixtures, and any inspection, sale or City notice.
2. Walk-through from the meter The service line material, the main shutoff, the pipe on each floor, and where walls, floors and ceilings can open.
3. Permit and repipe The permit filed for the address, new lines run and connected, then pressure tested and flushed before anything is closed.
4. Inspection and closing up The City or village inspection, labeled shutoffs, and the openings closed as the quote describes.

## What this work looks like

A new copper water line with soldered fittings along a wood ledger on a whitewashed brick basement wall

Lengths of new copper tube stacked on wood blocks on a basement floor

Copper water lines strapped across the underside of wood floor joists in a whitewashed brick basement

A new copper branch line through open wall studs with a soldered tee and brass ball valve

## Copper repiping questions

### Which type of copper pipe goes into a Chicago repipe?

Chicago's code lists Type K, L and M copper for water distribution, so the design chooses. Type K, the heaviest, is the code's material for a buried service line; L and M are the interior choices, and L has the thicker wall. A colored stripe, green for K, blue for L, red for M, lets the tube on site be checked against the quote.

### Is a press-connect copper joint as reliable as a soldered one?

Both are approved in Chicago, and each depends on being made right. A press joint relies on a sealing ring, full insertion and a tool certified by the fitting maker; a soldered joint relies on clean surfaces, correct heat and flux that is flushed out. The pressure test before walls close is where either kind proves itself.

### Can the main be copper and the rest of a Chicago house PEX?

No. Inside the City of Chicago, PEX has no entry in the water distribution table, and new and replaced supply pipe has to be a listed material, so the branches are copper too. Mixing materials is possible in suburbs whose codes list PEX, such as Oak Park and Skokie, where a copper main can feed PEX distribution.

### Will new copper pipe get pinhole leaks?

No one can promise it won't. Pinholes in copper come from more than one cause: water chemistry, high velocity in undersized lines, flux left inside joints and burrs left on cut ends. Sizing the lines for the fixtures, reaming cut ends, using flux sparingly and flushing after cutover address the workmanship causes. Chicago's corrosion control works in copper's favor.

### Do Evanston and Park Ridge require copper too?

Their codes say so. Evanston's plumbing code lists copper for water distribution, with Type L as the minimum above grade, and its water service table calls for Type K copper underground. Park Ridge's code bars CPVC, cross-linked polyethylene and polybutylene for water distribution and calls for Type L copper above ground. The rule is confirmed for the address before work starts.

## Related services

### Whole-house repiping

Whole-house repiping replaces every hot and cold supply line from the main shutoff to the fixtures in the material the local code lists, then pressure tests it before the walls close.

### Galvanized pipe replacement

Galvanized pipe replacement swaps restricted steel supply pipe for copper, with code-listed transitions wherever old pipe stays and a flush after every cutover to clear loosened scale.

### Two-flat repiping

The shared basement main, both units' risers and branches, and a shutoff in each apartment, planned around two households and one cutover.