How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes

Does a sink drain trap have to be plumb?

Sunday, November 1, 2020

"Traps shall be set level with respect to their water seals,” according to the International Residential Code (IRC P3201.3) and the Residential edition of the Florida Building Code (FBC). But the goofy angle of the trap shown above is only one of its problems. The trap is also installed backwards, creating an excessively tall trap seal, and the accordion-type piping makes the whole assembly guaranteed to clog. The trap shown at right is a much less egregious example, but needs to be correctly aligned with the tailpiece. 

    A plumbing trap must maintain enough water in it to prevent sewer gas from rising up into the house, but not so much that it creates a drain that is sluggish and easily clogged, and the interior surface of the pipe should be self-scouring. 

• • • • • • • • • • • • • • • • • • • • • • • • • • •

Here’s links to a collection of some of our other blog posts about PLUMBING DRAINS AND TRAPS:

 Why is it a problem when a trap under a sink is installed backwards? 

What causes a gurgling sound when a bathtub or sink drains? 

What is a "combination waste and vent" in a plumbing system? 

• What types of plumbing traps are illegal by code?

• Why is garbage disposal not allowed at a combination waste and vent (CW&V) under a sink?

What is a building trap?  

• What is a double trap in plumbing? 

• Can two sinks share a trap? 

 Why is the European-style bottle trap not approved by the plumbing codes in the U.S.? 

What is an auto vent, air admittance valve, or check vent?

Can I make a trap under the sink from straight pipe and 90º elbows?  

If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem?  

What is an "S-Trap" under my sink? Why is it a problem? 


What is a P-trap?

Is a sink required to have a drain stopper? 

• Can a laundry sink drain be installed without a trap under it? 

• What is a drum trap at a plumbing drain?

• Can a dishwasher drain hose be connected after the sink trap (to the trap arm)? 

• What is the minimum and maximum distance a P-trap can be below a sink? 

What is bell trap at a plumbing drain? 

     Visit our PLUMBING DRAINS AND TRAPS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

Water Heaters

Water Heater Age

"What Are The

Signs Of..."

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests

Sinkholes

Stairs

When It First

Became Code

"Should I Buy A..."

Park Model Homes

Site

Shingle Roofs

Safety

Stucco

Remodeling

Wind Mitigation

Roof and Attic

"Does A Home

Inspector...?"

Pool and Spa

"What Is The Difference Between..."

Radon

Brick

Plumbing

Concrete and

Concrete Block

Metal Roofs

Foundations

Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants

Condominiums

Older and

Historic Houses

Crawl Spaces

Mobile-Manufactured Homes

Building Permits

Life Expectancy

Clay Soil

Insurance

Floors

Insulation

Toilets

Exterior Walls

& Structures

Generators

Common Problems

HUD-Code for

Mobile Homes

Garages and Carports

Flat (Low Slope) Roofs

Electrical Panels

Sprinkler Systems

Electrical Receptacle Outlets

4-Point Inspections

Hurricane Resistance

Frequently Asked Questions (FAQ)

Home Inspection

Heating and Air Conditioning

Building Codes

Fireplaces and Chimneys

Inspector Licensing

& Standards

Energy Efficiency

Washers and Dryers

Electrical

Kitchens

Doors and Windows

(placeholder)

Cracks

Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps

Appliances

Smoke & CO Alarms

Aging in Place

Top 5 results given instantly.

Click on magnifying glass

for all search results.

Bathrooms

Lighting

AFCI, CAFCI,

DFCI, & GFCI

Sinks

Air Conditioner & Furnace Age/Size

Attics

Electrical Switches

Siding

Search

This

Site

Water Intrusion

Electrical - Old

and Obsolete

(placeholder)

Foundation Certifications

Tiny Houses

About McGarry and Madsen

(placeholder)

Wells

Buying a home in North/Central Florida? Check our price for a  team inspection by two FL-licensed contractors and inspectors. Over 8,500 inspections completed in 20+ years. In a hurry? We will get it done for you.

Moisture Problems

Crawl Spaces

Bedrooms

Closets