01Co-op vs. condo: the key difference
In a co-op, you own shares in a corporation that owns the building; the proprietary lease and house rules set what you maintain. In a condo, you own your unit and a share of the common elements; the declaration and bylaws define the boundary. In both, building-wide pipes like risers and stacks are usually the building's, while fixtures inside your home are usually yours, but the documents decide.
02Typical responsibility split
| Part of the plumbing | Rental apartment | Co-op | Condo |
|---|---|---|---|
| Fixtures inside the unit (faucet, toilet, sink) | Landlord | Usually the shareholder | Usually the unit owner |
| Branch pipes inside the unit's walls | Landlord | Depends on the proprietary lease | Depends on the declaration |
| Risers and stacks | Landlord | Usually the corporation | Usually the association (common element) |
| Damage to the unit below | Landlord / insurance | Lease terms + insurance | Declaration + insurance |
03When a leak damages another unit
- Stop the water and notify management right away.
- Management finds the source (often with a plumber) and determines whether it's a unit fixture or a building line.
- Repairs follow the responsibility split; damage is usually handled through each party's insurance.
- Keep photos, dates and invoices.
04Plumbing in a renovation
- Boards usually require an alteration agreement, plans, insurance certificates and licensed plumbers.
- Moving fixtures or changing branch lines usually needs a DOB filing in NYC, or a permit from the municipal construction office in NJ.
- Some buildings require their own plumber for anything touching a riser.
- Ask about the condition of the risers and stacks behind your walls before closing them up.
05Frequently asked questions
Who pays for a clogged stack in a co-op?
Usually the corporation, since stacks are building lines. If a clog was caused by misuse in one unit, the board may try to charge that shareholder.
Do I need board approval to replace a faucet?
Often not for like-for-like replacement, but check your house rules; many boards want notice and a licensed plumber.
06Related
Guides & rules
Sources & review
Last reviewed . General information, not legal or engineering advice. Rules change and individual buildings differ.