The plumbing system within your house takes the place of a hand dug well with a bucket and an outhouse. Hard to believe that a mere 100 years ago, only the rich folk had indoor plumbing. Believe it or not, only one percent of U.S. homes had indoor plumbing 1921 when Herbert Hoover was appointed Secretary of Commerce. These days, most of us have public water fed into the house by means of an underground piping system. There are, still, a fairly large number of residences in rural areas, which rely on private water wells. Most of these are either drilled or driven wells, with open dug wells pretty much a thing of the past.
Most of us also have municipal sewer systems to haul the waste away, although, like the wells, there are still a fair number of private septic systems still in use.
Here we will break down the main components within the plumbing system, in order to give you a better grasp as to how they operate.

• MAIN WATER SERVICE–
  • The majority of the water service pipes that we see these days are copper piping. Going back a number of years, lead pipes were used for these installations. There were also times where galvanized steel was used. Plastic piping is usually found feeding water from private wells.
  _o Copper – This piping is considered to be the best modern choice due to its durability and long service life.
  _o Galvanized – This piping has properties that lead to corrosion on the interior. This results in blockage over time,
  __ reduced flow and rust covered tint to the water. It generally has an expected service life of around 30.
  _o Lead – This piping was used during the early part of the 1900’s. The problem with lead piping is it may leach
  __ into the water supply. This metal can cause brain damage and delayed learning in some children. This is why we
  __ routine recommend that buyers of properties with lead water feeds have the water tested for lead content.
  _o Plastic – This piping is fairly durable and is found mostly on private wells. I would expect that it’s just a matter
  __ of time before this is improved to the point where it is found, large scale, on public water supplies.
  
• WATER SUPPLY SYSTEM –
  • Copper piping –
  _o Long lasting, usually trouble free.
  _o Lead-free solder is required in today’s plumbing standards.
  _o Hangers for this piping should be of like-material, as using galvanized strapping will allow corrosion to occur.
  • Galvanized Steel –
  _o Corrodes on the interior, resulting in a smaller diameter, reducing volume, and restricting flow.
  _o Used up through the 1950’s.
  _o Generally expected service life is in the neighborhood of 40-50 year. This places most of it outside the realm of ___typical service.
  _o Rarely do we find houses with the all of the original galvanized still in use. Most often, as least some of the
  __ piping has been changed over to copper.
  _o When galvanized/copper connections are made, special fittings are needed to prevent the two metals from
  __ contacting each other, as this will set off a chemical reaction, which accelerates rusting. These are called
  __ “dielectric fittings”
  _o Corrosion usually occurs near the joints first, as the threaded part is the thinnest area of the pipe.
  _o At times, changing out the horizontal piping will improve the water volume to an acceptable rate, as these pipes
  __ are more prone to collection sediment due to their orientation.
  _o Changing the “risers” feeding a second floor bathroom can be difficult, as often, they run vertical up to the floor
  __ level, then run horizontal under the bathroom floor. This is easiest when the bathroom is under major renovation.
  • Polybutylene piping –
  _o This piping was used extensively from the 1980’s through the early 1990’s. Thankfully, it never took off in our
  __ area, as it was found to be problematic.
  _o Many of the problems were due to improper installation, such as over-tightening the fasteners, resulting in
  __ hairline cracking.
  _o The amount of chlorine in the water has also be suspect to cause deterioration and potential leakage in
  __ these systems.
  _o Failure of the acetal plastic insert fittings was found to be a major cause of some failures.
  _o Newer, plastic pipe known as PEX (cross-linked polyethylene) is now available and becoming more popular,
  __ which has more resistance to stress cracks than polybutylene pipe.
  
• FIXTURES –
  
• DRAIN PIPING
  • Cast Iron –
  _o Cast iron drain piping was one of the mainstays in the plumbing drain industry from the early days when
  __ plumbing was brought indoors through the 1970’s.
  __- Upside –
  ___• Quiet, durable, continues to function in many homes today.
  __- Downside –
  ___• Susceptible to corrosion in many environments. Can clog up on the interior over time, slowing drainage,
  ____ or even creating blockages. Not easy to work with.
  • Galvanized Steel –
  o Most often found in tandem with cast iron. Was used extensively through the 1960’s.
  _- Upside –
  __• Um…much of it has been replaced over the years.
  _- Downside –
  __• Like the other metal plumbing pipes, it suffers from the effects of corrosion. It’s not unusual to come across
  __ drainage pipes that have corroded to the point where there is literally no center of the pipe remaining to drain
  __ through.
  • PVC (Polyvinyl Chloride) –
  o Commonly found in houses constructed from the late 1970’s through today.
  _- Upside –
  __• Environmentally friendly
  __• Provides long service life.
  __• Easy to install and handle.
  __• Corrosion resistant. Low occurrence of clogging.
  __• Cost effective.
  __• Widely accepted by building codes.
  _- Downside –
  __• “Easy to work with” increases the “Handyman” factor for improper workmanship.
  __• Low skill level required for working with PVC often leads to poorly installed drain systems.
  • ABS (Acrylonitrile-Butadiene-Styrene)-
  o Commonly found in houses built in the 1970’s up into the 1990’s. This is often referred to as the black PVC.
  _- Downside –
  __• There was a history of cracking problems with some of this piping. Five of the manufacturers of ABS pipe settled a class action lawsuit filed against them for problems with pipe manufactured between 1984 and 1990. The defective pipe tends to crack circumferentially at or near a joint or fitting. The cracking can potentially create leaks and cause water damage to the structure as well as promote the growth of mold. Not all of this piping manufactured between 1984 and 1990 has proven to be problematic and it is possible that pipe manufactured during this time frame by the involved manufacturers is performing as designed.
  • Copper –
  o The use of copper for drain lines was short-lived and is usually found in houses constructed in the 1960’s.
  _- Upside –
  __• This is generally found to be in good working condition and has a low propensity for clogging.
  __• Does not corrode in the fashion of cast iron or galvanized steel.
  o Downside –
  __• It limited lifespan was largely due to the high cost of the material.
  __• Cost, and the discovery of newer plastic piping lead to the demise of this product as an interior residential
  ___ drain pipe.
  __• Joints are sweated together, making it more time consuming that the newer plastics.
  
• DRAIN/WASTE VENT SYSTEM –
  • The purpose for this vent is to allow atmospheric pressure to assist in drainage of the system.
  • It is important that these pipes be terminated through the roof, as otherwise, methane gas (sewer gas) can be introduced into the house. Not only does this smell bad, it is also an explosive gas.
  
• COMMON PLUMBING PROBLEMS –
  WATER HEATERS – These appliances are found in all houses and provide hot water throughout the plumbing supply system to use for bathing, cleaning and cooking. There are several different types and are available to work with a wide range of fuel such as natural gas, liquid propane, fuel oil and electricity.
  
  • TYPES
  o 1)The most common water heaters seen in houses today are atmospherically vented tanks. This is due to the relatively low cost. Typically, they can be installed for less than $600.00. These have recently been changed in design to require a sealed combustion chamber. They will cost a bit more, although are considered to be safer.
  o 2) Next would be direct vent water heaters. These were designed to discharge the flue gas through the sidewall of a house. The vent system is fan assisted. A 40 gallon unit will run somewhere in the neighborhood of $1000.00 installed. Depending on the length of the vent piping, it may be advisable to have a condensate drain tube installed in the horizontal piping within a few feet of the vertical pipe that is exiting the top of the tank (the “riser”). This will protect the fan and internal components from damaging condensate if it runs back.
  o 3) Buildings that are heated with hot water boilers have the option of using what is referred to as a “side-arm” tank as their water heater. This combines two appliances into one, utilizing the boiler to heat the household water. Keep in mind that the potable (drinking) water is zoned and isolated from the heating piping. These systems are a good investment if you are using a boiler.
  o 4) We are now starting to see more and more “on-demand” water heaters. These are designed to fire up only when hot water is called for, and shut down as soon as the demand is over. This eliminates the burner firing up throughout the day as the water in the tank begins to cool. This saves energy, not to mention money. Plus, no more running out of hot water. The downside, they are quite a bit pricier that the other types of tanks, although with energy savings, they do end up paying for themselves over time. One other downside, if you have a large family, the energy costs generally are not realized as much as with a small family.
  
  • TPR VALVE (Temperature Pressure Relief Valve)
  o This valve is required on all water heaters. It is a safety valve whose importance cannot be overstressed. The purpose is to provide a means for reducing the pressure or temperature inside the tank in the event it rises above the maximum acceptable levels. Without this valve the tank could become a guided missile.
  
  Don’t believe me? Read this article from a Seattle newspaper:

Exploding water heater rocks suburban Seattle shopping center, injuring three
by Mia Penta, Associated Press, July 28, 2001

BURIEN, Wash. (AP) A suburban Seattle shopping center was rocked by a water heater explosion that hurtled concrete chunks for a block, shattered business facades and injured four people. The water heater at a video store in the shopping plaza rocketed through the building's roof, over a Taco Bell restaurant and into a Pizza Hut parking lot 460 feet away, said Battalion Chief Doug Hudson.
''The whole front of the Mexican restaurant, the video store and the grocery store blew out,'' said J.D. Burtis, who works at a recreational vehicle park across the street. ''They're totally shot. All the windows and glass are gone. There's counters laying on the front door.''
The water heater did not strike anyone in the Friday blast, but glass and bricks rained on parked cars and blanketed the four-lane road next to the building.
''Had there been more people in the business or anyone in the vehicles outside or had that water heater ... hit someone, we'd have a much more serious situation,'' Hudson said. Fire crews found four people dazed in the parking lot Friday, said Hudson. One, a 50-year-old Burien woman, was treated for second-degree burns to her right arm. She was in satisfactory condition Friday evening at Harborview Medical Center in Seattle, a nursing supervisor said. The others were taken to Highline Hospital in Burien with minor injuries.
Initial damage estimates were $750,000 to $1 million, said Bill Harm, King County assistant fire marshal.
The explosion was apparently caused by the electric water heater at a video store in the plaza, Puget Sound Energy spokeswoman Dorothy Bracken said.
''The pressure relief valve had been capped, and the tank was partially drained of water,'' Hudson said. ''It built up steam pressure. It was a steam explosion.'' The thermostat on the water heater also may have malfunctioned, Harm said. The owners of the video store told KIRO-TV that a repairman had been called to look at the water heater on Thursday because it was producing scalding water. They said the repairman told them the heater needed to be replaced, and that he had shut it off in the meantime. Jose Lopez, of Burien, was just getting out of his car at an insurance firm next door when he heard what he thought was an earthquake. "'I opened my door and 'boom!' and it exploded," Lopez said. "People started running out full of dust."