Plumbing Supply
The common concerns regarding the condition of the plumbing supply are for the water pressure, water quality and leakage. When referring to the condition of the plumbing supply we are referring to the pipes that service the water supply from the water meter (usually at the front of the house) to the taps and plumbing fixtures within the house.
Houses built in the 1970's and earlier were typically plumbed with a galvanized steel pipe and even earlier than that lead was used although this is rarely found in use now.
The two major problems with galvanized iron material are that the performance of the joins deteriorate with time causing leakage; and that corrosion forms on the inside of the pipe reducing water pressure and causing a rusty brown discolouration of the water - ultimately complete blockages occur.
Homes built after the late 1970's used copper material which is much more durable, the joins were welded and less prone to leakage and the water flow through the copper material is generally of a higher pressure and quality. A common problem of poor quality installations is water hammer and the water flow vibrations can lead to leaks in poorly welded joins.
Since the late 1990's the use of PVC pipes have become common they are connected at joins with brass or copper connecters and a special crimping tool. Currently this material is a favourite because of the speed with which an installation can be completed. However the material is prone to damage from contact with sharp edges and some plumbers complain that there is a small percentage of product failure that occurs within the crimped joints and spigot fittings.
Apart from the occupational inconveniences and frustrations of a failing plumbing supply such as weak water pressure and dirty tap water.
The most important point to note is that a failed plumbing supply is an extremely common contributing factor to structural movements in a building. Pre purchase building inspectors often find cracked brick work and sinking floor structures are a result of plumbing failures. The effects of leakage can contribute to extreme fluctuations in the moisture content of the foundation soils and in worst cases lead to sub surface erosion and complete undermining of a houses foundation.
The expense of a new plumbing installation is significant and usually requires updating all tap fittings and fixtures, for a standard brick veneer home of 20 squares the expense would be approximately $5,000 - $7,000.
A licensed plumber's inspection of the plumbing supply service could take half a day or more and would require the use of specialized testing apparatus and techniques that include removing tap sets and shutting down the water supply. When engaging a Pre Purchase Building Inspector, you are not getting the same standard of plumbing inspection that you would from a licensed plumber but you should get additional feed back on the age and material quality of the installation; and the visual standard of workmanship provided to repairs and renovations. You should also get a professional opinion on the likely need for a new plumbing supply installation and or recommendation for further investigation by a licensed plumber.
Article written by Jason Wier B. Eng (Building) principal Inspection Angel 2007.
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