How close does the p-trap need to be to the fixture?
The vertical distance from a trap to the fixture outlet shall not exceed 24 inches.
According to the International Residential Code, the maximum vertical distance between the sink drain and the entrance to the p-trap is 24 inches.
Code requires the vent to be no farther than 6ft away from the drain opening. Are you saying the space between the floor and the ceiling is not large enough to accommodate a trap?
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Distance of fixture trap from vent.
| Size of Fixture Drain, Inches | Distance Trap to Vent |
|---|---|
| 1-1/4 | 2 ft 6 in |
| 1-1/2 | 3 ft 6 in |
| 2 | 5 feet |
| 3 | 6 feet |
A trap arm shall be permitted to change direction without the use of a cleanout where such change of direction does not exceed 90 degrees (1.57 rad).
P-501.2 Prohibited Traps
Any trap whose seal depends upon the action of movable parts; Any trap with interior partitions, except when integral with vitrified clay plumbing fixtures; Double traps, unless a fresh air inlet is connected to the system between the traps; Crown-vented traps.
If you have 1 ¼-inch pipe, the horizontal distance of the vent should not be more than 30 inches. For a 1 ½-inc pipe the vent should be 42 inches away at the most while a 2-inch pipe must have a maximum distance of 5 feet.
A trap arm of 2” pipe at a 1/4” slope, for example, is listed at 8 feet maximum length.
When the trap is too deep, liquid may flow through it too fast, which can lead to siphoning of the trap seal and sludge buildup. The drain connection at the wall is too high on this sink, resulting in a 9-inch-deep trap seal — 5 inches deeper than is allowed by code.
There is no minimum distance specified by the building code, but the maximum is 24” per International Residential Code (IRC) and Residential Edition of Florida Building Code (FBC 1002.1), measured from fixture outlet to trap weir.
How far down can p-trap be from shower drain?
In the state I live in the P trap needs to be under the shower as the drop from the shower drain to the trap is required to be vertical and less than 24 inches. Vertical is however defined as 45 degrees or more from horizontal, so one could be somewhat off of center of the drain.
It's a bad plumbing practice to have a hard 90-degree bend in a horizontal drain line that's buried in a slab or otherwise hidden. If you have to make a 90-degree bend, use two 45-degree fittings and put a small piece of straight pipe between the fittings, if possible.
When builders look only at the table without reading the text, they find that a 2-inch-diameter drain can run a maximum distance of 8 feet to the vent.
Trap Primer valve makeup line to floor drain is recommended to be a minimum of 12” off the finished floor before a 90° elbow can be installed. The furthest recommended distance of makeup line is 20' to the floor drain.
The simple answer is if your trap from the fixture cannot see the vent then it is installed wrong. We must always keep the vent connection above the trap weir to prevent siphoning and keep proper pressures on both side of the trap.
The “S” trap is prohibited under the Uniform Plumbing Code throughout the United States. This is because the “S” trap will siphon or suck water out from the trap which will end up releasing methane (sewer) gases into the home. So, it is a code violation and if you are doing remodeling, you will have to replace it.
Trap arms that are too short or too long are an installation issue. Siphoning the trap or blocking the vent pipe are the implications of trap arms that are too long or too short.
| DIAMETER OF PIPE (inches) | MAXIMUM NUMBER OF DRAINAGE FIXTURE UNITS (dfu) | |
|---|---|---|
| 2 | 6 | 24 |
| 21/2 | 12 | 42 |
| 3 | 20 | 72 |
| 4 | 160 | 500 |
1004.1 Prohibited
"S" traps, bell traps, and crown-vented traps shall be prohibited. No fixture shall be double trapped.
Each fixture trap shall have a water seal of not less than two (2) inches (51 mm) and not more than four (4) inches (102 mm), except where a deeper seal is found necessary by the Authority Having Jurisdiction.
What is a rule of etiquette for setting traps and running trap lines?
In addition to checking traps daily, follow these rules of etiquette for setting traps and running traplines: Whether or not an animal has been caught, check to see that sets are in proper working order. When possible, make sets to cause immediate submersion and death.
P-traps need vents
1 – They give the sewer gases a place to vent, so they do not build pressure inside your sewer lines.
Each fixture trap shall have a protecting vent located so that the slope and the developed length in the fixture drain from the trap weir to the vent fitting are within the limits indicated in Table P3105.
Wet vents are typically used when plumbing a bathroom group. So yes the shower can also be vented by the wet vent along with the toilet. There is one major stipulation when wet venting multiple fixtures when a toilet is one of them: the toilet must be the last fixture connected to the wet vent.
In general, the maximum distance of the toilet from the main drain should not exceed 4 meters, with a 2% minimum slope. Within these limits, the plumbing system can guarantee an effective draining, avoiding bad smells and the problem of emptying the siphons.