What are the common fittings used in plumbing?

Author: scraper  |  Last update: Tuesday, September 29, 2026

Common plumbing fittings are essential components used to connect, extend, terminate, or change the direction and size of pipes. They act as the puzzle pieces that safely route water supply and wastewater throughout a building.

What is the most common plumbing fitting?

Tee fittings get their name from their resemblance to the letter “T”. These fittings are one of the most common types of pipe fittings you will find in plumbing systems. This is because tee fittings are versatile and easy to manufacture. Tee fittings can be used to divert, merge, or redirect flow in a plumbing system.

What is the 135 rule in plumbing?

The "135-degree rule" in plumbing states that the total (aggregate) horizontal change in direction for a drainage pipe—specifically trap arms—cannot exceed 135 degrees between the P-trap and the vent. Exceeding 135 degrees (such as using three 45-degree bends or a 90 and two 45s) requires a cleanout because sharp turns hinder flow and cause clogs.

Why don't plumbers like pex?

Leaks and Fittings Issues

PEX plumbing uses fittings and connectors that are typically made of plastic or metal. Over time, these fittings can loosen, leading to leaks. Problems can arise with crimp rings, as improper use of a crimping tool can weaken the joints.

Do new houses use PEX or copper?

Did you know that PEX piping is used in about 60% of new construction projects to date? This makes it a prevalent material used in new buildings.

Every Type of Plumbing Fitting EXPLAINED

What does vinegar do to PVC pipe?

Effects on Metal and PVC Pipes

While harmless for most metal and PVC pipes, prolonged exposure to the acidic nature of vinegar might corrode certain metals, like copper. PVC pipes, on the other hand, can withstand these substances without damage.

What should never go down the drain?

To protect your plumbing and the environment, you should never put fats, starches, harsh chemicals, or solid waste down your drains.

What is a 90 degree fitting called in plumbing?

Street 90-Degree Elbow

Street 90-degree elbows have one end designed to fit directly into a fitting or valve without a connecting pipe. They can be used when a pipe needs to be connected to a valve or fitting at an angle. They are also commonly used when changing the flow direction in underground piping systems.

What are the most common plumbing code violations?

Here are the most common plumbing code violations you might not even realize you have—and why they matter.

  1. Improper Drain Slopes. ...
  2. Missing or Inadequate Cleanouts. ...
  3. S-Traps Instead of P-Traps. ...
  4. No Air Gap on Dishwashers. ...
  5. Incorrect Pipe Materials or Connections. ...
  6. Unpermitted or Uninspected Work. ...
  7. Water Heater Code Issues.

What are the most common fitting failures?

Trending Issues in Pipe Fitting Failures

  • Material Incompatibility and Corrosion. Corrosion is among the biggest sources of pipe fitting failure. ...
  • Poor Installation Practices. A large percentage of pipe fitting failure occurs during installation. ...
  • Pressure Surges and Overloading. ...
  • Temperature-Related Failures.

Is it better to use PVC or pex?

PEX is generally better for indoor water supply lines because it is flexible, resists bursting in freezing temperatures, and handles both hot and cold water. However, PVC is superior for outdoor, high-pressure use and drainage, as it is rigid and cannot be used for hot water.

What are the three common pipe fittings?

Common fittings are couplings, ells, and tees.

What is the number one killer of plumbers?

PMRs for malignancies of the stomach, kidney, brain, and lymphopoietic system were also elevated, especially among plumbers. Chronic rheumatic heart disease, emphysema, liver cirrhosis, and all external causes of death were the major non-cancer causes with significantly elevated PMRs.

What 5 tools are most common in plumbing?

The five most common and essential tools used in plumbing include specialized wrenches, cutting tools, and grip gear necessary for pipes and fixtures.

What fitting closes the end of a pipe?

Caps and plugs are fittings used to close off the end of the piping run. Caps are designed to fit over the outside of the pipe and attach via threading or brazing methods, while plugs are designed to fit inside of the pipe and attach via threading.

Can you have bends on a toilet waste pipe?

as long as it has an adequate fall on it to the soil stack. Personally, I would avoid putting 90degree bends on a sewage disposal system. However, If you really have no alternative, and you have a good substantial fall, you may get away from possible blockages.

What is a figure 5 fitting in plumbing?

A "Figure 5 fitting" (also called a double-fixture fitting) is a specialized plumbing connector used in Drain, Waste, and Vent (DWV) systems. It allows two fixtures on opposite sides of a wall (such as back-to-back toilets or sinks) to connect to a single vertical drainpipe without waste from one fixture flowing into the other.

Why pour salt down the drain every night?

Pouring salt down your drain at night is a popular DIY plumbing trick used for routine maintenance. The goal is to take advantage of the salt's coarse texture and natural moisture-absorbing properties.

What is the 3 drain rule?

Stepping over three drains is considered bad luck (Image: Penny Cross / Plymouth Live) "Superstitions can be seen as fun and light-hearted, but for some people they are unshakeable rules to live by.

What do plumbers recommend instead of Drano?

Drano Alternatives – What can you substitute for Drano?

  • Baking Soda and White Vinegar – Drano Alternatives. Baking soda and white vinegar are sustainable substitutions for Drano. ...
  • Soap and Hot Water – Drano Alternatives. ...
  • Salt and Water – Drano Alternatives. ...
  • Plunger – Drano Alternative.

Does Dawn really unclog drains?

A straightforward yet effective approach to addressing a clogged drain pipe involves simply using hot water mixed with dish soap. This method, ideal for tackling minor blockages, leverages the degreasing power of dish soap combined with the force of hot water to dislodge and dissolve clog-causing residue.

Why shouldn't you pour boiling water down the drain?

Pouring boiling water down your drain can soften and warp PVC pipes, weaken the glue in pipe joints, and damage rubber gaskets. Instead of clearing grease, boiling water just melts it, pushing it further down the pipe where it hardens and creates a stubborn, hidden clog.

Why shouldn't you use baking soda and vinegar to unclog a drain?

Baking soda and vinegar do not effectively unclog drains. Instead of clearing debris, mixing them chemically neutralizes both ingredients into salt water. The fizzing reaction is visually satisfying but largely escapes upwards, offering zero power to dissolve grease, hair, or stubborn sludge.

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