How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes


Thursday, May 17, 2018

Here’s links to a collection of our blog posts about “PLUMBING":

Is black iron gas pipe code approved for exterior (outdoor) installation?

The cover plate of my water meter box is broken. Who is responsible to fix it? 

Honey, who shrunk the toilet? 

How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

Is a double heating element water heater better than a single element water heater?

Can galvanized steel pipe still be used for new water lines in a house? 

Can a water meter box (vault) be installed below ground level (grade)?

How can I tell if I have cast iron pipes in my house? 

Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?

Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

Why is a damaged hose faucet handle a safety defect?

Is a washing machine drain hose required to be secured at the standpipe?

What are the abandoned pipes sticking out of the wall in my house?  

What is the difference between green and white sewer drain pipes?

Why is the vacuum breaker at my hose faucet leaking, gushing water, or making funny sounds?

Why is the cover plate of some water meter boxes in the ground painted purple?

• How do I find the main water shut off valve for my house? 

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

What are the code requirements for plumbing vent terminations?

What are the code requirements for layout of drain piping under sinks?

Why is there sand in the bottom of my toilet tank?  

What are the building code requirements for gray water reuse in Florida?

What is the difference between a sill cock, hose bibb, hose faucet, outdoor faucet, and hose spigot?

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

Does a water heater need a shut-off valve?

How can I tell the difference between Corrugated Stainless Steel Tubing (CSST) and a Flexible Appliance Connector (FAC)?

Is it normal to smell gas near a natural gas meter? 

 What is the difference between a vent stack and a stack vent?

What is a "fixture unit" for plumbing? 

Are drop-in toilet bowl cleaner tablets safe?

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

What causes water dripping down the flue (condensation) at a gas water heater?

How does a retrofit hot water recirculation system work?

What can I add to my septic tank to help it work better? 

What are the minimum requirements for a shower?

Why do septic tank contractors want you to get rid of your kitchen disposal? 

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

Why is there mold inside my toilet tank?  

Does a "QEST" brand mark on pipe mean that it is polbutylene (PB)?

What is a building trap?  

What are the pros and cons of a wall-mounted toilet?

Does a refrigerator water supply line require a shutoff valve behind it?

What is a galvanized nipple?

Which plumbing fixtures require water shut off valves in a home? 

Is a hot water faucet required at a washing machine?

What is a sediment trap or dirt leg? 

What are the pipes sticking out near my water valves?

Can PEX pipe be installed outside?  

 Is PEX pipe freeze resistant?

What is an indirect waste receptor? 

How do you accurately find a broken water pipe leak under the floor slab?

What is the difference between water pipe and sewage (waste) pipe? 

How can I tell if a house is connected to a septic tank system or sewer?

What is the average life expectancy of PEX pipe? 

What type water supply and drain (DWV) pipes were commonly used for 1990s residential plumbing?

What is the average life expectancy of galvanized steel pipe? 

What is the average life expectancy of cast iron pipe?

What type water supply and drain (DWV) pipes were commonly used for 1970s residential plumbing?  

Should I seal the washing machine drain hose to the standpipe?

What type water supply and drain (DWV) pipes were commonly used for 1960s residential plumbing? 

What type water supply and drain (DWV) pipes were commonly used for 1950s residential plumbing?

Are plastic pipes (PVC, CPVC, and PEX) safe for drinking water? 

What do the ABS, PVC, CPVC, PB, and PEX plumbing pipe names mean?

Why is a backflow preventer required on lawn sprinkler systems? 

How can I locate my septic tank?

Does a septic tank have to be re-certified if a house has been vacant for a while?

• Does code require a water shut-off valve for dishwashers? 

Is a shut off valve in-line on a supply line to a plumbing fixture acceptable?

Is a hot water faucet handle required to be on the left? 

Can you live in a house while the plumbing is being replaced?

What is the loose wire sticking out of the ground under the gas meter for? 

Why is sunlight exposure bad for PVC pipe?

What is an escutcheon plate? 

What are the requirements for installing a gas appliance connector?

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?

What is the average life expectancy of PVC pipe? 

Why can't PVC be used for water pipe inside a house?

What is the average life expectancy of copper pipe? 

What are the common problems to look for when the plumbing has been replaced in a house? 

What is a dielectric union? 

What's that powdery crust on the pipe connections at the water heater? 

Why are rubber washing machine hoses a safety risk? 

What are the minimum clearances around a toilet? 

What is that pipe sticking out of the ground in the yard? 

What are the black metal things marked GMX800 that are clamped around the hot and cold pipes above the water heater?

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

What type of white plastic pipe has the marking CP-112-P in red letters? 

What is the little tank on top of the water heater for? 

What is a grinder pump? 

How do you test a shower pan for leaks?

What is a saddle valve?

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

How can I tell what type of plumbing pipe I have?

Why is there a flexible accordion pipe under the sink? 

What is the difference between PVC and ABS plumbing pipe?

What is that big thing in the toilet tank? 

What is the difference between a plumbing fixture, a plumbing appliance, and a plumbing appurtenance?

Is a replacement water heater required to have a pan with a drain? 

What causes low water pressure in a house?

What is the difference between water service pipe and water supply pipe? 

How often should I pump out the septic tank?

Should I call a plumber or septic tank contractor when my septic tank backs up into the house? 

Do I have to get a larger septic tank when I build a home addition?

How do I get rid of the sewer gas smell in my house?  

What are the pipes on my roof? 

Should I wrap the water heater with an insulation blanket? 

My water bill went way up last month. How do I look for a leak?

Why are shower water valves all single-handle nowadays? 

What is a "cross connection" in a home's plumbing system?

Why does the water have a rotten-egg smell in some empty houses? 

What is the white plastic tank inside my toilet tank?

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

What is a P-trap?

Where is the septic tank? Are you going to inspect it? 

Why is old galvanized steel water pipe a problem for homebuyers?

What does polybutylene pipe look like? Why is it a problem?

Which water pipes are an insurance problem and possibly uninsurable? 

• Does a home inspector check the plumbing under the floor slab?

What is the difference between gray water and black water in the plumbing code? 

• Is it alright to disconnect the washing machine drain from the septic tank and divert it to the ground in the yard?

• What is the difference between regular tap water and recycled/reclaimed water for landscape irrigation? 

• What problems are caused by connecting copper pipe/tubing directly to galvanized steel pipe?

What are the most common plumbing problems with older houses? 

Is a shower pan leak test a required part of a home inspection?

Why is some PVC pipe black?

• Can I install a commercial (wall-mounted flushometer) toilet in my home? 

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?

Does a home inspector check toilets? 

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

How far away from the sink can I install a dishwasher? 

What is a "high drain loop" or "air gap" in a dishwasher drain hose?

When were shower control valves first required by code to be pressure balanced and temperature limiting? 

When were the water control valves for bathtubs first required to be temperature limiting (single handle)? 

 Is a vacuum  breaker required by code at hose bibbs (outside faucets)? 

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

• Is an air admittance valve (AAV) legal by code? 

• What is a double trap in plumbing? 

• Can two sinks share a trap? 

• How close can electrical be to plumbing in a house? 

• What is a bell trap at a plumbing drain? 

• What plumbing traps are illegal by code? 

• What is a plumbing cross connection?

What is the average life expectancy of a sink? 

Can a plumbing vent terminate in the attic?

• Does code require an access panel for a whirlpool spa tub? 

How many hose bibbs (outdoor faucets) are required by code for a house?

What is the minimum and maximum slope of the trap arm of a plumbing drain? 

What is the minimum trap arm length?

• Why is my water meter box full of water? 

• Do I need a vacuum breaker valve for washing machine hose faucets? 

• What is the code minimum size of a dishwasher water supply line?

Water Heaters

Water Heater Age

"What Are The

Signs Of..."

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests



When It First

Became Code

"Should I Buy A..."

Park Model Homes


Shingle Roofs




Wind Mitigation

Roof and Attic

"Does A Home


Pool and Spa

"What Is The Difference Between..."




Concrete and

Concrete Block

Metal Roofs


Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants


Older and

Historic Houses

Crawl Spaces

Mobile-Manufactured Homes

Building Permits

Life Expectancy

Clay Soil





Exterior Walls

& Structures


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



Doors and Windows



Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps


Smoke & CO Alarms

Aging in Place

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Air Conditioner & Furnace Age/Size


Electrical Switches





Water Intrusion

Electrical - Old

and Obsolete


Foundation Certifications

Tiny Houses

About McGarry and Madsen



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.

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