Water pipe size at the building shut-off, hints from a home inspector
Water pipe size as viewed at the building shut-off: the inspector will circle one of the sizes.
12 Inch is the smallest supply line acceptable. Usually you will notice a water flow problem when several faucets are turned on. Consider replacing the line with a larger one as time and finances permit.
34 Inch is a very common size supply line. It is somewhat better than the 12 inch line but still has shortcomings if the building is very large. Again, it is recommended that you budget money for replacement with a larger line as time and money permit. 1 Inch supply lines are common in newer construction. This line size should be sufficient for a single family residence or small commercial building if it is not older than 20 years and if the area water is not heavily laden with minerals.
1-14 Inch supply lines are uncommon in residential construction. Flow problems with this size pipe should be uncommon unless it supplies a large number of apartments or a very large commercial building.
1-12 Inch and larger water supply pipes are generally used only in apartment complexes and large commercial buildings. Note: the inspector cannot ascertain whether leaks exist within the water lines unless they are readily visible. Pipes which are buried beneath the ground or in or beneath concrete slabs are obviously not visible. Sometimes, on quiet nights, you may hear a hissing sound in your pipes. This may be an indication that a leak is ongoing in the water lines. It is recommended that you contact the local water supply company and ask for assistance in determining whether there are leaks.
The above information was provided by TWI Systems Copyright 1995-2007 1-800-553-5660. TWI is a fantastic company to deal with!
