In most municipalities you can do rough in plumbing in your own home yourself provided you follow plumbing codes and municipal building standards. If you’re thinking of doing some rough in plumbing yourself, you need to be sure you understand the building code in your area and check with your local municipality as to the specific law in your area. As well, even when you’re allowed to do the plumbing yourself, be sure to have your finished work inspected by a certified plumber or building inspector to ensure all parts of your final implementation do meet the local codes.
A plumbing plan is the first step in roughing in plumbing
Before you ever drill a hole or connect a pipe you first need to prepare a plumbing plan that outlines what and where all of your plumbing is going to be placed. This plan includes the water inlet system, the drainage system and the vent lines for all of the fixtures. It also needs to describe the materials you are going to use for each of the systems (copper, PEX PVC) as well as the size of the pipes.
A rough in plumbing plan has a list of all the fixtures you’re going to install and their precise location in your home. Fixtures covers a wide range of items when we’re talking rough plumbing and includes standard fixtures like toilets, showers, sinks and wash basins as well as some electric appliances you might not think of as fixtures, things like washing machines and dishwashers.
It’s also a good idea to include provision for any additional fixtures you may be thinking of adding in the near future. Making provision for them now could save considerable expense a few years down the road.
Home plumbing consists of three systems that need to work together, the DWV system (drainage, waste and vent system) and the water inlet system for plumbing to work.
The DWV system is actually two systems working together as one. The drainage components include the waste stack - the central point of the drainage system and all the drainage pipes from each fixture. All the drainage pipes in the house flow into the waste stack and it in turn carries wastewater out of the building and into the main sewer system. The main stack is usually a 3 or 4 inch pipe that runs from the bottom of the house right up through the roof while drainage pipes are usually 2” PVC.
The other vital part of the DWV system is the vent system itself. The waste stack couldn’t flow without air, so each waste pipe or drain is connected to a vent that is in turn connected to a network of fresh air inlets running up to the roof. Air actually balances the plumbing system, and air pressure in the plumbing pipes allows traps in the pipes to retain water that blocks sewer gases from entering the home.
Water Inlet system
Water comes into a home through a ¾ or 1 inch pipe under pressure through the main water shut off (and water meter). Once inside the water supply splits into two, one for cold water and one for hot water (this runs directly into the hot water tank). Smaller riser pipes carry hot and cold water together to each of the fixtures and appliances in the home.