What Adapter For

How to connect PVC to galvanized pipe

Glue a PVC male adapter (slip x MPT) onto the PVC and screw it into a female thread on the steel, such as a steel fitting or coupling. PVC and steel water pipe share iron pipe sizes, so no size change is needed.

What fits

A PVC male adapter screwed into the steel pipe’s female thread

On the package: PVC male adapter (slip x MPT) in your pipe’s size

both are iron pipe size, so a 1/2" adapter fits 1/2" steel pipe thread

Available on Amazon

PVC male adapter, slip x MPT PTFE thread seal tape

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  • Shut the water off, then open faucets to drain the pipes before you cut anything.
  • Glue the adapter onto the PVC with primer and cement, wrap tape on its male threads, and screw it into the steel fitting. Plastic male into metal female suits cold water.
  • Tighten the PVC adapter with a strap wrench only, two turns past finger tight at most.
  • If the steel pipe ends in male threads, add a steel or brass female coupling first. Steel male threads screwed into a PVC female fitting put very high stress on the plastic, so that joint isn’t recommended.
  • SharkBite’s PVC fittings aren’t for galvanized pipe.

PVC is glued and galvanized steel is threaded, so a glue-on adapter with pipe thread joins them.

Before you start

  • Make sure the steel pipe carries water. Gas supply lines can be black iron or steel pipe too. When in doubt, call a licensed plumber or your local gas company.
  • Rusted fittings and rust-colored water, particularly from hot water lines, are signs of advanced deterioration in galvanized pipe.
  • If a lead service line ever fed this galvanized pipe, lead can cling to its inside and get into the water. Ask your water utility about testing.

PVC to galvanized drain pipe

In a drain line, PVC and steel pipe of one size have the same outside diameter: 1-1/2" pipe is 1.900" across and 2" pipe 2.375". Fernco’s 1056 couplings join plastic or steel to cast iron, plastic or steel, and are sized by the pipes’ outside diameter. Its 1056-150 takes 1.73" to 2.00" on each end, and its 1056-22 takes 2.20" to 2.50".

Fernco makes these couplings for drain, waste, vent and sewer lines, never for water under pressure. Between plastic and other drain pipe, the IPC and IRC call for an approved adapter fitting. Local code decides which fittings are approved where you live.

Common questions

Can I run PVC off a galvanized line inside the house?

The IPC's table of pipe for water lines inside the house lists CPVC but not PVC, and Charlotte Pipe rates PVC to 140°F at most. Local code decides what can run indoors where you live.

Do I need a dielectric union between PVC and galvanized pipe?

The codes ask for a dielectric or brass fitting where copper meets galvanized steel. PVC to steel falls under their plastic pipe rule instead, which asks for an approved adapter fitting.

Keep going

Connecting different pipePVC to copperPEX to galvanizedCPVC to galvanizedPipe thread sizeWhat pipe do I have?Garden hose to 1/2" pipe

For a different part on either end, open the adapter finder with this pair picked.

Where we get our information from

The sizes on this page come from published standards and the makers’ own documents. Checked against published data from International Code Council, Oatey, SharkBite, US EPA and Charlotte Pipe (plus 7 more).

See all 20 sources
  • National Bureau of Standards, Handbook H28 (1957) Part II: Table VII.2 (American Standard taper pipe threads, NPT) and Tables X.1–X.3 (hose coupling threads, NH)
  • JM Eagle, PVC Schedule 40/80 submittal (ASTM D1785 outside diameters)
  • Swagelok, Thread Sealants catalog (MS-14-01): PTFE tape, how to apply
  • Oatey, Solvent Welding Instruction Guide
  • Reliance Worldwide, SharkBite PVC Fittings Sales & Specifications Sheet (2015): white collar fits Schedule 40, 80 and 120 PVC
  • US EPA, Customer Guide for Identifying Service Lines (2024): scratch and magnet tests, galvanized downstream of lead
  • US EPA, Basic Information about Lead in Drinking Water
  • HUD, Residential Rehabilitation Inspection Guide (2000): water supply piping, fuel supply
  • Charlotte Pipe, Plastics Technical Manual (2026): PVC and CPVC colors, standards, temperature limits, Not for Pressure print, plastic-to-metal threads and brass transition fittings
  • International Plumbing Code 2021, sections 605.23, 605.23.1 and 605.23.2: joints between different materials, copper to galvanized steel (as adopted in South Carolina)
  • International Residential Code 2021, sections P2906.18 and P2906.18.1-P2906.18.3: joints between different materials, PVC service to CPVC (as adopted in South Carolina)
  • Charlotte Pipe, Plastics Technical Manual (2026), product data: average outside diameter and minimum wall of PVC Schedule 40 and 80, PVC DWV, PVC and ABS foam core, 4" sewer and drain pipe, and CTS CPVC
  • Wheatland Tube, Standard Pipe (SureThread and ERW) brochure: ASTM A53 Schedule 40 and 80 outside diameter, inside diameter and wall, black and galvanized, ASME B36.10M
  • International Plumbing Code 2018 (as adopted in Georgia and Oklahoma), 2021 and 2024 (as adopted in South Carolina), section 202 (building drain, building sewer) and sections 705.2, 705.3.2, 705.3.3, 705.10, 705.16 and 705.16.4: ABS, cast iron and PVC joints, joints between different materials, plastic to other piping, the one ABS to PVC solvent-cement joint (ASTM D3138)
  • International Residential Code 2021, sections P3003.13 and P3003.13.4: joints between different drain materials, plastic to other piping, the one ABS to PVC solvent-cement joint (as adopted in South Carolina)
  • Fernco, Standard Flexible Couplings page: series by pipe pair (1002 clay, 1056 cast iron, plastic or steel), outside diameter ranges per part, above and below ground, Strong Back RC for buried joints, 60 in-lb torque, ASTM C1173, not for pressurized water
  • International Plumbing Code 2021, sections 605.14.2 (CPVC solvent cementing, ASTM F493), 605.21.3 (PVC solvent cementing, ASTM F656 primer and D2564 cement) and Table 605.4 (water distribution pipe) (as adopted in South Carolina)
  • SharkBite (RWC), How to Turn Off Main Water Valve for Plumbing Repairs (SharkBite blog): shut the water off for repairs, then open the faucets to drain the pipes before the work, isolation valves for one fixture, turn the water back on slowly
  • Oatey, How to Replace and Install a Shut Off Valve (project guide): turn off the water supply before removing or cutting off the old valve
  • BrassCraft, Easy 3-Step Gas Connections how-to sheet (BC8472): when in doubt, call a licensed plumber or your local gas company

General guidance from manufacturer and standards data. Parts vary by brand, so check the size printed on the package against what you measured. This site doesn't cover gas lines. If in doubt about gas, call a licensed plumber or your local gas company.