01Overview
More than half of NYC homes are in buildings built before 1947, so many still have original galvanized steel water pipes and cast-iron drains, often mixed with copper or PEX from later renovations. Each material ages in its own way. See pipe materials, compared.
A spot repair fixes one failure. Repiping replaces the water supply (and sometimes drain) piping throughout, which makes sense when failures are widespread or walls are already open for a renovation.
02Signs you may need this
- Repeated pinhole leaks in copper
- Rusty or brown water when a tap first opens
- Weak flow upstairs or at several fixtures
- Visible rust, green deposits or wet spots on exposed pipes
- Pipes that froze or burst in winter
- A gray, soft water service line where it enters the building (possible lead)
03Common causes
| Material | Typical problem | What it leads to |
|---|---|---|
| Galvanized steel | Internal corrosion and buildup | Low pressure, rusty water, leaks at threads |
| Cast iron (drains) | Rust-through, cracks, scale | Leaks in the cellar ceiling, slow drains |
| Copper | Pinhole corrosion in some conditions | Small leaks, often repeated |
| Lead (service line) | Health concern for drinking water | Replacement recommended |
| Any material | Freezing | Split pipes and fittings |
Inside an old galvanized pipe: corrosion narrows the opening, causing low pressure and rusty water.
04Possible solutions
| Option | When it fits |
|---|---|
| Spot repair | One failure on otherwise sound pipe |
| Partial repipe | One problem area: a bathroom, a riser, a floor |
| Full repipe (copper or PEX) | Widespread corrosion, low pressure everywhere, or a gut renovation |
| Cast-iron section replacement | Rusted-through or cracked drain sections |
| Service line replacement | Lead, galvanized or failing lines from the street |
The right approach depends on what the plumber finds on site. This table is general information, not a diagnosis.
Repiping with PEX and copper while walls are open.
05What affects the cost
Prices are set by the plumber and depend on what's found. These factors usually matter most:
- How much pipe is replaced and how accessible it is
- Material choice (copper or PEX)
- Opening and closing walls and ceilings
- Number of floors and fixtures
- Permits, inspections and city or utility coordination
06What a plumber typically checks
- Identifies the materials in the building and where they change
- Checks flow and pressure at fixtures on each floor
- Inspects exposed pipes for corrosion and past repairs
- Checks the service line material
- Recommends spot repair or repiping, with a plan for access and water shutoffs
07By building type
- Brownstones & rowhouses
- Original galvanized and cast iron are common; repiping often goes with renovation.
- Two- & three-family houses
- Repiping by unit or the whole house; tenants need a plan for water shutoffs.
- Apartment buildings
- Repiping inside an apartment connects to building risers; coordinate with management.
- Suburban houses
- Copper and PEX are common; frozen pipes in garages, crawlspaces and exterior walls.
08Local considerations
New York City
NYC DEP reported at least 130,000 known lead service lines and about 200,000 of unknown material in 2024. DEP's online map shows the status for your building. Repiping in NYC is filed with DOB by a Licensed Master Plumber.
Long Island, Westchester & Hudson Valley
Frozen pipes are the main winter risk. Insulating pipes on exterior walls and in unheated spaces, and shutting off outside faucets, prevents most of them.
New Jersey
Under a 2021 state law, New Jersey water utilities must replace lead service lines, generally within 10 years, so you may get a letter from your utility. Interior repiping is permitted work through the construction office.
09Permits & licensing
- NYC: repiping is filed with DOB by a Licensed Master Plumber, usually through a Limited Alteration Application
- New Jersey: permit and inspection through the municipal construction office
- Co-ops & condos: board approval and alteration agreement are usually required
Rules differ by jurisdiction. Compare NYC, Long Island, Westchester and New Jersey.
10Frequently asked questions
Copper or PEX for repiping?
Both are widely used. PEX is flexible and needs fewer fittings and smaller openings; copper is rigid and long-established. Local code and the plumber's experience decide which is used where.
How do I know if my service line is lead?
In NYC, check the DEP service line map for your building. A plumber can also look at the pipe where it enters: lead is dull gray, soft and shows a shiny silver scratch. In NJ, your utility's inventory should list it.
Can I stay at home during repiping?
Often yes. Water is shut off in stages, usually during working hours. The plumber should give you a shutoff schedule.
11Pipe Repair & Repiping by area
Local guides
We take calls about pipe repair & repiping across the region. Choose your area for local building and permit details.
New York City
Long Island & Hudson Valley
New Jersey
12Related
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Sources & review
Last reviewed . General information, not legal or engineering advice. Rules change and individual buildings differ.