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Two Family House Repiping in NYC

For interwar attached and semi-detached two-families in Queens and Brooklyn, with an owner on one floor and a tenant on the other.

By NYC Repipe & Repair · Last reviewed

New copper branches serve two stacked kitchens in an attached brick two-family
New copper branches serve two stacked kitchens in an attached brick two-family. Illustrative.

NYC Repipe & Repair repipes two-family houses across New York City, replacing the hot and cold supply for both units in Type L copper under one DOB permit. Two family house repiping differs from a one-family job in three ways: the house may have one water meter or two, one floor is often tenant-occupied and has to stay on water, and each unit may have its own water heater. The common stock is interwar attached brick in Queens and semi-detached houses in Brooklyn.

What happens on the first visit

  1. Pressure readings in both units, so the upstairs loss is measured, not guessed.
  2. Meters, water heaters and the service line located, and pipe material identified.
  3. Routes planned for each unit, with shutoffs scheduled around the tenant.
  4. A written price for both units, including the permit and testing, before booking.

The houses and why they need it

The typical NYC two-family is interwar. In Queens, 59% of one- to four-family lots were built between 1920 and 1949, median 1935 (MapPLUTO): the attached brick of Jackson Heights and Sunnyside, the brick rowhouses of Ridgewood, the two-families of South Ozone Park. In Brooklyn, Bensonhurst and Bay Ridge have 1910s–1930s attached and semi-detached brick. Nearly all were plumbed in galvanized steel, which typically lasts 40 to 60 years, and soft, corrosive city water speeds the decline: DEP’s annual water quality report puts the average Langelier index at −2.21.

The symptoms split by floor. The upstairs unit loses pressure first, because rise costs pressure and rust narrows the pipe; the downstairs unit tends to get the leaks. Both together mean the system has failed, not one joint (low water pressure, galvanized pipe replacement).

One meter or two, and the tenant upstairs

Some two-families have one water meter; some have two. With two, the new copper keeps each unit on its own meter and water heater; with one, the layout can be simpler. Where each unit has its own water heater, each gets its own hot line and shutoff, so one unit can be worked on while the other keeps hot water. The first visit settles which you have.

The tenant matters more than the pipe. NYC owners must provide hot water at a constant 120°F, 365 days a year (NYC HPD). Shutoffs are scheduled and short, the house is normally back on water at the end of each working day, and the job typically takes five to ten working days.

Copper, permits and the price

A Queens owner on a HeatingHelp thread asked whether to repipe a South Ozone Park two-family in copper or PEX. Inside NYC it’s copper: Table 605.4 doesn’t list PEX (copper vs PEX in NYC). Joints are soldered or permanent press; removable push-fit is prohibited (PC 605.9).

A two-family files as a 1–3 family LAA: $130 up to $5,000 of work, plus $2.60 per $1,000, so a $20,000 job carries a $169 fee. Unpermitted work draws penalties from $520. Published prices for a 2–3 story house run $12,000–$30,000+ (A Good Plumber). Buying? Read buying a house with galvanized pipes. For method and numbers, see whole house repiping and repiping cost in NYC.

What's included

  • Type L copper supply for both units (ASTM B88)
  • Each unit kept on its own meter and heater
  • New shutoffs at every fixture and each unit
  • Lead-free valves and fittings to NSF 372
  • Dielectric or brass transitions where needed
  • DOB NOW permit filed by a NYC Licensed Master Plumber
  • Pressure test before walls are closed
  • Shutoff schedule agreed for the tenant's unit
Weak pressure upstairs, leaks downstairs? Pressure readings in both units show whether it's one joint or the whole system. (929) 659-6658

The permit trail

What a legal NYC repipe leaves on the record

Every permitted repipe produces the same paper trail at the Department of Buildings. It's what a buyer's attorney, a co-op board or a lender will look for later.

  1. DOB NOW: Build Filed

    Limited Alteration Application

    Filed by the Licensed Master Plumber, with the scope and the job cost.

  2. DOB Issued

    Work permit

    Issued in real time for most repipes, and posted at the job.

  3. On site Installed

    Type L copper in

    Run alongside the old pipe and switched over section by section.

  4. Plumbing Code §108 Tested

    Pressure test

    The whole new system holds under test before walls close.

  5. DOB Signed off

    Inspection and sign-off

    The job closes cleanly on the building's DOB record.

Three ways it gets done

Patch, cheap repipe, or permitted copper

Three ways NYC pipe work gets done. Only one survives a co-op board, a refinance and the next winter.

What matters DIY patchCheap operatorPermitted copper job
Pipe material Whatever the hardware store sells, often PEXPEX or thin Type M copper to save moneyType L copper, listed in NYC Plumbing Code Table 605.4
Fittings Push-fit connectors (prohibited, PC 605.9)Mixed: some push-fit, some solderSoldered or permanent press joints; dielectric unions at steel
Who may legally do it Not the owner: NYC requires a Licensed Master PlumberOften unlicensed, or a licence borrowed for the filingA NYC Licensed Master Plumber, or a crew under one
Permit NoneOften skipped (penalties start at $520, or $6,000 in 3+ family buildings)Filed in DOB NOW and signed off
Pressure test NoneRarelyWhole system tested before walls close
Co-op or condo board Will not approveUsually rejected at the insurance-certificate stageMeets typical alteration-agreement requirements
At sale or refinance Unpermitted work can surface in inspectionOpen DOB issues can delay closingA clean DOB record for the job

Sources: 2022 NYC Plumbing Code, Chapter 6; NYC DOB LAA fee and penalty charts (1–3 family, other buildings).

From the field

What two family house repiping looks like in an NYC house

Illustrative photographs of typical conditions and the copper that replaces them.

Two new water meters side by side on new copper lines in the basement of a two-family house in Queens, painted block wallTwo gas water heaters side by side in a Queens basement with new bare copper water connections and brass valves on each

Answered

Two Family House Repiping, answered

Can my tenant stay in the house during the repipe?

Yes. The new copper runs parallel to the old pipe and each section is switched over in turn, so the house is normally back on water at the end of each working day. Shutoffs are scheduled in advance, and the tenant's hot water connection is planned first.

Is PEX allowed in a two-family house in NYC?

No. Table 605.4 of the 2022 NYC Plumbing Code lists brass, copper and copper-alloy pipe, copper tubing Types K and L, ductile iron and stainless steel for water distribution. New York State's code outside the city allows PEX in two-family houses, which causes the confusion.

Should the copper be crimped or soldered?

Either soldered joints or permanent press fittings made with a manufacturer-certified tool meet NYC code for copper. "Crimp" usually means PEX fittings, which don't apply here. Removable push-fit fittings are prohibited by PC 605.9 in either unit. The same rules apply to the main and risers shared by both floors.

Do both units have to be repiped at once?

No, but it is usually cheaper. The main and risers are shared, so doing them once serves both floors. Staging the second unit's branches later is legitimate but costs more in total because walls are opened twice. Each stage should be filed and pressure-tested on its own.

Who actually does the plumbing work?

In New York City, permitted plumbing work must be performed by a NYC Licensed Master Plumber or by workers under an LMP's direct supervision, and the LMP files the permit in DOB NOW. Ask any contractor for the LMP's licence number before work starts, and check it on the DOB's public licence search.

Get your two family house repiping priced in writing

Pressure measured, pipe identified, an itemized price including the DOB permit.

The job · step 1 of 2
☎ (929) 659-6658 Free estimate