Tub Supply Line Buying Guide


Use the following informational tips when deciding which supply lines will work best for your bathroom layout. Please note that codes and ordinances may vary. When in doubt, consult a local professional when deciding which supply lines to buy.
  Double Offset Water Supply Lines  
  Double offset supply lines are most popular for wall-mount faucets with 3-3/8" centers. The supply tubing is angled and slopes slightly outward from the faucet. At the floor, the plumbing for double offset supplies should be roughed in at 8" on centers.  
  Single Offset Supply Lines  
  Single offset supply lines are used when the roughed-in pipe at the floor is aligned with the tub faucet holes. If the faucet has 3-3/8" centers, the supply lines will be roughed in at 3-3/8" centers. If the faucet has 8" centers, the supply lines will be roughed in at 8" centers.  
  Pressure Balance Supply Kits  
  Pressure balance supply kits are a variation on the double offset supply lines. Pressure balance kits work by maintaining a constant temperature at the faucet, which means they will not be affected by changes in water pressure. Although they do not have a thermostat to regulate a maximum temperature, they can protect against sudden spikes or drops in temperature, such as those caused by a flushing a toilet or running water from another source in the home.  
  Straight Supply Lines  
  Straight Supply Lines are used for deck or rim-mount faucets. These supply lines are aligned with the tub faucet holes. For a tub faucet with 7" centers, the supply lines would be roughed-in at 7" on centers in the floor.  
  Freestanding Tub Supplies  
  Freestanding supply lines are made from heavy duty brass tubing that is designed to support the weight of the faucet. The supply lines must be securely anchored to the floor of the home. Some supplies also require wall supports. Centers vary depending on the spread of the faucet. Most applications will use 7" centers.  
  Bathcock Couplings  
  Tub supply couplings are required when using braided supply lines, instead of one of the types of decorative lines listed above. You might use braided supply lines for two reasons:
(1) Your tub and faucet are up against a wall, so your supply lines are hidden, or
(2) Your water supply is coming from the wall instead of the floor (like with the previous options).

Braided supply lines will not fit your tub mount faucet alone, so these couplings are necessary to attach the lines to your faucet.

Additional Information and Instructions

•  All supply lines should be installed by a qualified, licensed plumber. We suggest that rough-in work is carried out with the tub on site to avoid costly mistakes.
•  Supply lines are made from high quality cast brass. These lines cannot be bent to vary the spread at the floor. If you have plumbing roughed in on unusual centers, it is suggested to either change the plumbing rough-in or use tub ells with braided water lines.
•  Supply lines (except freestanding lines) can be easily cut with a tubing cutter to the correct length for installation.
•  Tub supply lines are available with or without shutoff valves that allow you to shut the water off at the tub in the event of a water leak.
•  Avoid over-tightening all connections. Snug the nuts by hand. Using a box wrench, tighten 1/4 turn. Check for leaks. Tighten 1/8 of a turn until leaks stop. Cast brass is one of the best materials known for plumbing pipes and valves, but it will crack or split if over-tightened.
•  Use Teflon tape on supply line threads instead of plumber's putty for the best water tight seal.