This means that you would typically want your water lines to be at least 4.5 feet below the ground level or possibly even deeper if you live in the mountains or the foothills. The sewer lateral leading from your house out to the municipal sewer main should also be at the same depth as it could also freeze.
The top of the pipe should be buried not less than 1 foot (0.3 m) below the frost line. In those locations where frost is not a factor, the depth of cover should be not less than 2- 1/2 feet (0.8 m) to prevent mechanical damage. Pipe should be buried below the frost line when entering streams and other bodies of water.
Spoke with my colleague: California Plumbing Code 2007 Edition (news to me): Section 609.1 states: Minimum cover shall be 12" below finish grade or minimum 12" below the local frost depth. So, 18" below finish grade will be fine and I know on occasion, you get frost in Danville (rarely).
Typically, water lines are buried at a depth ranging from 18 inches to 5 feet, depending on various factors such as local climate, soil conditions, and the type of water system in place.
Pipe for conveying liquids susceptible to freezing should be buried no less than 12" below the maximum frost level. Permanent lines subject to heavy traffic should have a minimum cover of 24". For light traffic, 12" to 18" is normally sufficient for small diameter pipe (typically < 3" diameter).
The standard depth for water lines in the U.S. is around 36 inches, but this can vary from location to location.
Dig-up test results in the U.S. and around the world indicate that PVC pipe can be expected to provide reliable service in excess of 100 years.
The water line size for a residential home is usually a ¾” to 1” diameter pipe.
It is recommended to use a 'blank cap end' (made from plastic or rubber) with a purpose-made hole with a grommet to allow the water pipe to pass through. The water pipe should be laid at depth of 750mm (minimum) to 1350mm (maximum). Trenches should be lined and backfilled with sand or soft earth, not rubble.
Eighteen to 24 inches is fine in most cases.
It's not just a pipe dream, because you can still do it on your own! Running water lines in your house comes down to knowing what tools you'll need, and how to use them to repair or install brand new pipes.
PVC. Polyvinyl chloride (PVC) is one of the most common types of piping, and it can be used for underground water supply in some applications.
When connecting a toilet soil pipe, it is advised to never use a pipe smaller than 100mm to carry the waste from said toilets. This size soil pipe is not designed to handle solid waste and can result in a blockage. So 110mm soil pipe is important to consider in this instance.
Running a PEX line underground is beneficial because of the pipe's flexibility, temperature resistance, and lack of a need for multiple connections along its length. In areas with aggressive soil or water conditions, plastic or brass PEX fittings are recommended.
Your water line must be buried at least 12 inches below the frost line to meet local code requirements. However, a minimum depth of 6 inches below the frost line is often recommended for extra security against freezing.
It should be at least 1” inside diameter pipe ID going into the house or larger and 3/4 ID on all runs in the home with at least 1/2 ID going to each point of use . Otherwise if you are taking a shower and hot water is used somewhere else you will get a cold shock .
When you are digging the trench for your new waterline, be sure the waterline is 12-inches below the local frost depth, but in no case less than 2 feet underground.
TRAFFIC LOADS
The minimum depth of bury for PVC pipe with traffic loading is twelve inches from the top of the pipe to the bottom of the flexible road surface.
If trench is to be a joint trench (shared with other utilities) the following separations must be maintained: 24 inches between gas and electric lines. 12 inches between water and electric lines. 24 inches between sewer and electric lines.
Copper pipes can last anywhere from six months to the life of a building. But PEX tubing, when operating within its pressure and temperature ratings, has a predicted life expectancy of 50 years per PPI TR-3.
Polyvinyl Chloride (PVC) Pipe PVC pipes are widely used in new water main connections.
A quick and easy way to increase water pressure is to adjust the pressure-reducing valve, which can be found in your home, usually close to your water meter. If your pressure gauge reading was low, make slight adjustments to your regulator.
PVC and CPVC are more cost-effective than PEX if you price clients by the hour, as they require many fittings secured by clamps cement. PVC and CPVC have more strength and durability than PEX because they are more rigid, making them better suited to outdoor applications where the piping may be subjected to trauma.
On average, PEX pipes can last anywhere from 40 to 50 years, and in some cases, even longer.
PVC pipe schedules can range from 10 to 160 but schedules 40, 80, and 120 are the most commonly used for underground applications.