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Your bathrooms can be the most wonderful or disgusting places in a home. These rooms are so often used that parts such as fans, faucets, drawers, cabinets, showerheads and more can easily deteriorate over a short amount of time. Inspecting a bathroom isn’t just as simple as turning the water faucets on and off. It’s also taking the necessary tests to ensure no moisture exists in the walls near or surrounding any area prone to water damage. Water damage can be subtle and easily deteriorate a wall behind a tub or below a sink over time. It’s best to allow a qualified professional inspector from US Inspect to perform the analysis.


Most people take for granted the benefits of plumbing systems and fixtures—carrying the drinking water to, and the waste water from, your home. Even more seldom consider the various components and issues involving plumbing. The following pages outline various components and key considerations to help you evaluate your system.

The purpose of the plumbing system is to provide an adequate supply of potable water and to properly dispose of waste products.

Domestic Water Supply - Source

Public Water Supply
Municipal (city water)

To determine if the property uses city water, the best indication is a water meter. In older constructions, the water meters might be located outside in a front yard pit or at the front curb. In modern construction, water meters are usually located inside the basement, frequently with a remote digital reading device located on the outside of the building.

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How can you tell whether your water service pipe is made of copper, steel, lead or plastic?
Simply scrape the pipe material at the wall where the pipe enters the house. Copper is relatively soft and has a copper penny color. Galvanized steel is hard and has a silver-gray color. Lead is fairly soft. You will only see this type of service piping in homes that are about 100 years old. The joint where the lead has been sweated to the supply piping looks like a bulb or a short section of expanded pipe. It has a gray color.

Plastic piping will have a metal clamp where it joins the supply piping. Plastic service pipe is generally blue, tan or white in color.

How can you tell if poor water pressure is caused by problems with the supply piping or the service piping?
Consistently poor water pressure indicates that there is a problem with the supply piping (or the main source of water).

Water pressure that is acceptable for one or two seconds, then diminishes, indicates that there is a problem with the service piping that comes from the street to the house.

The reason for this is different pipe sizes. The service pipe is typically larger than the supply piping. If the supply piping is corroded or restricted, water will exhibit a consistently weak pressure. On the contrary, if the supply piping is good and the service pipe is corroded or restricted, the supply piping will fill and provide good volume for only a second or two, because the corroded service pipe will not be able to keep the supply piping filled.

How can you determine the condition of failing steel supply piping  before the water pressure becomes poor?
Look for small roundish rust warts or growths on the outside of the piping. Rust warts are failures that start from the inside of the pipe and come through the surface of the pipe. They typically do not leak immediately, but will usually start leaking within one year.

How can you tell when the well water is deteriorating the copper piping simply by looking at the house?
Look around the drains of the sinks and the tubs. If you see green patina stains in these plumbing fixtures, then it is a good indication that the well water is acidic and that the copper is being deteriorated. In extreme situations, round green stains can be seen on the horizontal runs of the pipes. These are failures, and will start leaking with a small spray of water. The solution is to test the water and install a neutralizing system to raise the water’s pH level.

Note: Brown-orange stains indicate excessive minerals in the water. Conditioning equipment is strongly recommended if this is the case.

How long does cast iron soil pipe last and where will the first failure typically occur?

Cast iron soil or drain pipe will generally be dependable for 60+ years. The first failures usually occur in the horizontal section of pipe, at about 8'–20' past or below the vertical vent pipe.  This failure develops on the top of the pipe. The reasons for the failure in the top of the pipe and at this specific location are:

The acids produced by the human digestive system (aka methane gas) deteriorates the top interior portion of the pipe. The bottom has moisture and a small amount of solids, and the acid doesn’t have the same impact.

The horizontal pipe is installed at a 1/8''–1/4'' slope towards the sewer in the street. The slope is necessary to provide fall that will allow gravity to drain the waste and to allow the liquid waste to mix with the solid waste so that both will exit the pipe. If there is too much slope in the pipe, the liquids will not adequately mix with the solids. The reduced friction will cause the liquid to drain quickly and cause the solids to lay in the bottom of the pipe. The solids will not clog or stop the flow, however, they will allow the acids to accumulate in one area and deteriorate the top of the pipe.

When waste drops in the vertical vent pipe from a bathroom, it will rush through the first 8' or so of the horizontal pipe. At this point, the liquid waste still has momentum while the solids have started to slow. Turbulence in this 8'-20' area is what is what accelerates the deterioration process inside the top portion of the pipe.


Note: In some cases, the vertical section of pipe is the first to fail. This is due more to workmanship than acid deterioration. The vertical section of pipe can weigh 300–400 pounds, depending on the height. If it is not supported or hung properly, the stresses and natural deterioration may cause failure in 60 or so years.

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Shutoff and Traps

Hot & Cold Sink Supply Lines/Shutoffs
There are small faucet knobs that control and shut off the flow of water for both the hot and cold water for the lavatory(s) as well as a cold supply for the toilet and/or bidet.  Usually these faucets will have a ½-inch copper pipe coming in to the shutoff and have 3/8 or 1/4-inch tubing from the shutoff to the lavatory faucet or toilet

Plumbing Traps
In order to prevent sewer gasses and odors from entering the house, plumbing drains were designed long ago with "traps".  A trap is a section of the drain piping, usually directly under the drain, that forms an "S". The drain pipe forms a 180-degree curve followed directly by another 180-degree curve. These "S" traps are no longer recommend and are outlawed at some locations. The pipe can also form a "P," (recommended) and the drain pipe forms a 180-degree curve followed by a 90-degree curve. The trap or curves in these pipe are designed to allow the water to drain, but allow residual water to remain behind and act as a barrier to unwanted sewer gasses escaping up the drain pipe and into the home.

The point to remember is it's necessary that a drain pipe be designed with a trap installed in order to prevent sewer gasses from entering the house’s breathable airspace.

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Fan and Vent

The sink, tub and especially the shower introduce a lot of moisture into the bathroom. Therefore, proper ventilation of the bathroom is essential to prevent mold, rot or other moisture-related problems. Exhaust fans and vents are installed to ventilate and remove moisture in all new bathrooms. The fan unit is usually ceiling-mounted and directs the air through a vent to the exterior of the house. Though now generaly required on new homes, older houses often make use of a window instead of exhaust fans to ventilate the bathroom.

A common problem with exhaust fans and vents is when the vent terminates someplace other than the exterior of the building. Improperly terminated exhaust vents typically terminate in the attic, which causes excessive moisture in the attic. This buildup of excessive moisture can lead to moisture-related problems such as wood rot in the structural components of the home.

Many exhaust fans do more than just vent. Additionally, exhaust fans integrate normal incandescent or neon lighting within the fan housing. Some even integrate infrared heat lamps to warm the bathroom.

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Sinks and Cabinets

The actual term for sink is “lavatory,” sometimes called “lavs.”  If the sink bowl is mounted on a pedestal instead of a cabinet base, then it is called a “pedestal sink.”  Most sink bowls and pedestals are constructed of cast vitreous china, similar to toilets.  However, you may find sinks made of glass, acrylic, steel, cast iron, or anything else that will hold water.  Each type of material has its own advantages and disadvantages.

One of the more common types of sinks is the cultured marble or stone sink.  This is much like a plaster-of-Paris that is poured into a mold and finished with a plastic layer. Cultured marble sink tops are popular because the entire cabinet counter top is usually formed as an integral part of the lavatory.

As with the large variety of "lavs" choices, the choices of lavatory faucets are also widely varied.  It is important that they be capable of being turned on and off repeatedly, day in and day out, for many, many years. They are designed for both aesthetic appeal and longevity

Similar to the cabinets in the kitchen, sink-base cabinets in bathrooms are the standard storage space.  There are two basic methods of construction--face-framed and faceless. In face-framed construction, the cabinet body has a hardwood or plywood-framed face to which the doors are attached. In frameless construction, as the name implies, there is no face and the doors are attached directly to the cabinet body. Approximately two-thirds of the cabinets in the U.S. are made in the face-framed manner.

Cabinets are made of a wide variety of materials, the most common being plywood or compressed particleboard. The counter top is anchored to the top of the cabinets.

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Bathtubs are very simple fixtures designed to contain water, fit one or two people, and drain spent water into the sewer system. As civilization has progressed, so has the development of bathtub design.  Bathtubs are made in a multitude of sizes, shapes, colors and configurations.

Bathtubs are either built into alcoves in the bathroom or are freestanding. They can range from the old-fashioned, stand-alone claw foot tub to an ultra-modern, computerized jetted tub that delivers and maintains a set water temperature.  The standard size for a tub is 5 feet long and approximately 2 feet deep.   
Tub materials can range from enamel-coated cast iron to injection-molded plastic. Other materials include fiberglass, stamped steel and molded acrylic. Tubs made from cast iron are considered to be preferable due to their durability and their ability to retain water temperature. However, cast iron tubs tend to be very heavy.  Tubs made from acrylic that is reinforced with fiberglass are also considered to be very good. They are lighter than cast iron tubs and, due to the nature of acrylics, are able to be molded into very intricate shapes, including contoured seats and steps. Some tubs are made of fiberglass, however, these tend to fade when in direct sunlight. They also are not very resistant to scratching and impact damage.

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Ceramic Tile

There are two basic methods of setting ceramic tile. Wet-bed systems, mostly in older properties, are made up of a cement base or ground coat over wire lath. A second cement coat will receive the tiles. After the tiles are set and allowed to dry, the tiles can be grouted. Wet-bed systems are superior to mastic systems. About half of the showers with lead pan bases tend to fail in the 45 to 55-year range. You may wish to cover the drain with a wash cloth or small towel, assuming there is no drain plug, fill the base of the shower with 3 to 4 inches of water, turn the water off and remove the wash cloth or towel. Wait 5 minutes and check the ceiling below. Tap and gently press on the tiles around the perimeter of the bottom 3 courses of a shower stall, around the faucets of a tub or shower and at the sidewall of a tub, closer to the front to look for loose tiles, which may indicate deteriorated or water damaged substrate.

Modern tile is placed directly onto a green board, which is drywall with a small amount of asphalt in the paper to make it water-resistant. The tiles are then set in a mastic or adhesive designed for this application. Grouting of the tile can be done the next day. Tile systems set over water-resistant drywall or sheetrock has a typical life expectancy of 10 to 14 years in a shower and 12 to 16 years in a tub/shower situation. Check the areas around the bottom of the shower and at the faucets and wall closest to the faucets in the tub/shower situation. A better mastic system is installed with a waterproof substrate, such as wonder board, which is a cementious board, instead of the water-resistant gypsum drywall board.

Plastic Tile
Plastic tile is a low-end material and is usually not installed in modern construction.

Fiberglass Tub/Shower
Fiberglass tubs and showers are less expensive and relatively common in new construction. The newer units are superior to older units because older units are thinner, and tend to crack and discolor. Modern fiberglass is more stable, the bottoms are thicker, easily supported, and do not crack like some of the older mid-1970's tub units. After you have reviewed the ceiling below, the best way to check for problems is to stand in the unit in about the same position you would if you were taking a shower. From this position, look for cracks to the outsides of your feet. Some units will only leak with someone standing in the tub. This is especially common with 20-25 year old units.

Hardboard, such as Marilite, is an inexpensive compressed board with a glossy finish. The life expectancy is 5 to 7 years in a tub/shower that is used daily. Water has a tendency to leak into the edges of this material. This moisture is absorbed into the hardboard and the finish separates.

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There is actually some debate over who and when the modern flush toilet was invented, but generally it is mistakenly attributed to a plumber named Thomas Crapper in early nineteenth century England.  The modern toilet has a two-fold purpose. The first well known purpose is to move the waste into the septic or sewer system.  The second purpose is to prevent sewer gasses from entering the house.  Due to the simple ingeniousness of the design, unless the toilet is physically damaged or incorrectly installed, it performs this function without fail.

Basic Designs
There are two basic designs used in residential dwellings--one-piece and two-piece.  With the two-piece, the tank that stores the water to perform the actual flush function is separate from the the bowl, where the waste is deposited.  The tank may either sit directly on the bowl or may be elevated above the bowl and connected by a pipe. In one-piece construction, the bowl and tank are cast as one single piece.  Both types are usually made of vitreous china casting and operate the same.

Basic Operation
When a toilet is ready for use, both the tank and the bowl are partially filled with water. As the toilet is flushed, the water in the tank enters the bowl which forces the water in the bowl through the drain channel. The velocity of the water draining creates a level of suction which pulls the contents of the toilet bowl down the drain. Once the tank is empty, the tank and bowl slowly refill.

Trapping the Sewer Gas
If you were to look at a cross section of a toilet, from the bowl to the drain in the floor, you would see an S-shaped channel. The S-shaped channel acts as a trap that keeps the water level in the bowl equal to the highest part of the S-shaped channel. The channel prevents sewer gasses from entering the house by maintaining water in the bowl.

Flush Valve Assembly
The flush valve assembly is the mechanism inside the tank that regulates the water during the flush operation of the toilet.  This assembly usually consists of the following components. A float ball,  called the ballcock, is attached to the inlet valve. The ball rises and falls with the water level in the tank.  When the ball rises to a certain level, the inlet valve controlling the incoming water is turned off and  the tank stops filling.  The water enters the tank through an inlet tube to the inlet valve and down through the fill tube.  The fill tube is used to direct the water into the tank.

The flapper is a rubber or plastic flap at the bottom of the tank.  The flap covers the opening, called the flush valve seat.  When the toilet handle is operated, the flapper is lifted, which causes the water in the tank to enter the toilet bowl.

The tanks on older toilets vary in size/capacity from 5 to 7 gallons.  All new toilets are required to be 1.6 gallons or less.

The most common point where a toilet leaks is at the junction between the toilet base and the floor.  The base of the toilet has a ringed opening that fits into the sewer or septic plumbing called the toilet flange.  The flange is a recessed ring that is attached to the sub-flooring and floor framing.  To seal the connection, a large ring of beeswax (old method) or heavy petroleum wax (newer method), which acts as a compression gasket, is placed between the toilet and flange to prevent liquid and gas from leaking. The toilet bowl is then secured to the floor with two bolts, located on the left and right side of the base.

Applying excessive or uneven pressure can cause the petroleum seal to become deformed and the connection to become loose and leak. Since these gaskets are not elastic, they do not have a “memory.”  (When compressed, the seal keeps the compressed shape and does not return to its original shape.)  So by applying an uneven or excessive pressure to the bowl, the wax ring becomes deformed and no longer seals the connection.    

Small failures of the seal will result in small leaks. Larger problems with the seal will be evident by the ability to move the toilet bowl side to side in a rocking motion. To fix the problem, completely replace the wax ring.  Additional repairs may be needed if any damage to the subflooring, framing or piping is found. Rubber gaskets with a "memory" are available on the market but are not widely used.    

Other leaks may develop if the bowl or tank cracks, or if the junction between the tank and bowl (two-piece) fails. Leaks between the tank and bowl occur when the bolts securing the tank to the bowl become loose or when the rubber "O" ring gasket that seals the connection rots or tears. To fix the problem, replace the rubber "O" ring gasket or tighten the bolt. Cracked toilets need to be replaced.  (Note: Over-tightening of bolts may crack the toilet.) 

Flush Valve Mechanism
Another common toilet problem is the tank constantly refilling  The constant refilling occurs when the flap does not properly seal with the flush seat.  This is caused by sediment or film build-up at the opening or by the flap becoming damaged or deformed. To fix, simply clean the opening and/or replace the flap.

If the handle used to flush the toilet no longer works, the chain or string that connects to the flap may be broken. When the handle is pressed, the chain lifts the flap, allowing the water to enter the bowl. The chain or string may wear out over time. To fix, replace the chain.

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Common Defects

  • Leaks in waste or supply lines or at fixtures
  • Orangeburg pipe – problems are age or tree root-related
  • Disposal of gray water into an unapproved septic system
  • Deteriorated piping and unacceptable "S" traps, etc.
  • Improper slopes, improper toilet valves, improperly supported pipes
  • Older galvanized pipe. Look for rust warts and or restricted flow
  • Life pumps, lift stations. Check operation; limited access
  • Improper venting
  • Not through roof; vents into attic
  • Roof vents too close to windows or ventilators
  • Water heaters – Non existent or improper temperature pressure relief valve extensions (TPRV)
  • Hot and cold supply lines reversed
  • Loose, deteriorated wall materials at bath/shower areas. (i.e. tile)
  • Residual chlorine in well water. May indicate ongoing bacteria problem
  • Lead in water – screening test
  • Polybutylene (PB) piping. Look for leaks and crimped joints
  • Back drafting of water heaters or furnaces
  • Water too hot (Over 140F)
  • Loose toilets at the base
  • Waste systems need attention
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