Operating Systems Home Inspection from A to Z - DVD Flash Videos

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Operating Systems Home Inspection from A to Z - DVD Videos. Real Estate Home Inspection, Appraisal, Energy Saving Home Improvements.-Operating Systems Home Inspection from A to Z - DVD Videos. Real Estate Home Inspection, Appraisal, Energy Saving Home Improvements.


Plumbing System

Plumbing System photos: P 49-P 56

The basic operation of a plumbing system is this:

  1. The water enters the house through the water main pipe from the city water main in the street. If the house has an on-site well, then the water main pipe comes from the well.

  2. From this main pipe, the water is then carried to different parts of the house by the supply water pipes. Supply pipes branch out in different directions to bring the water to the faucets.

  3. After the water is used at a faucet or shower it goes into the drain. This dirty water is carried back by drainage branch lines to a main drainage line.

  4. The main drainage line then carries the dirty water to the municipal sewer system in the street. If the house has a septic system, the dirty water is carried to an on-site septic system for disposal.

Look at all visible plumbing lines. There will be very little to view in a finished basement or behind walls and ceilings. Check for any corrosion, leaks or for any buildup of mineral deposits. Often you'll see water stains on some of the floor joists, which are the beams that support the floor above. You'll also see water stains on the sub flooring, which is the base for the floor above. Minor water stains are normal, especially underneath kitchens and baths. You need to be concerned about extensive water damage. If any doubts exist, check the floor above the damaged or stained areas. Try bouncing on the floor above during your interior inspection to make sure that it's solid and doesn't have a spongy feel.

  • There are two sets of plumbing lines:

  • One type is the Supply lines which are the thinner lines. They're about one inch or less in diameter. Water in the supply lines is under pressure.

  • The other type is the Drainage and Vent lines, which are about 3-6 inches in diameter. Water in the drainage lines is not under pressure because it's for drainage. The water in these pipes flows by gravity instead of pressure.

The vents in a plumbing system are used to allow air from the exterior to enter the plumbing drainage system. They usually protrude through the roof top by one foot. Sometimes on older houses or commercial buildings you will see a goose neck vent pipe on the sidewalk in front of the property. Vent pipes keep the pressure in the drainage lines equal to the atmospheric pressure of outside air. Atmospheric pressure is the normal air pressure outside the house. The reason for this is so the plumbing lines drain properly. Improper air pressure in these lines will cause a gurgling sound in the sink and tub drains. This gurgling sound indicates that the water isn't draining properly.

The "U" under the sinks is designed to trap water so that the sewer gases don't follow the drainage lines back into the house. There should also be a "U" installed on the main drainage line. It should be near the point where the main drain line goes through the foundation wall and out into the street. Sometimes this "U " is not installed or not visible. If the plumbing lines don't drain properly, then the water in the "U " trap can be drawn out. The water is drawn out by the suction of the draining water. If this happens, there will be nothing to stop the sewer smell from entering the house through the sink drains. The "U" is not installed to catch jewelry and other objects that are dropped down the sink drain; contrary to what some people might think.

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