In-Home Plumbing

Household plumbing is the final stretch of distribution before your water reaches the faucet, showerhead, or toilet basin.

Generally, in-home plumbing system represent the network of water flow between where the water enters the home from the utility distribution system or private well (the Point-of-Entry or POE), and where the water flow exits the distribution network (the Point-of-Use or POU).

POE and POU not only distinguish the scope of your in-home plumbing system, but they also can dictate where in-home treatment systems can be placed (see In-Home Filters).


Knowing the material used to construct your in-home plumbing system is essential to monitor your drinking water quality.

Dominating in-home plumbing is two distinctive tubing materials: plastic (non-metallic) and metal (metallic).


Metallic piping is still commonly found in homes throughout the state of Michigan. Two common metallic plumbing materials are copper and galvanized steel. These materials are often favored over their plastic counterpart due to increased durability, especially for long-serving water supply lines. However, with a potential for corrosion, metallic piping may leach toxic soluble compounds, or ions, into drinking water as they age.


Plastic, or non-metallic, piping such as Polyvinyl Chloride (PVC), Chlorinated Polyvinyl Chloride (CPVC), and Cross-Linked Polyethylene (PEX), have been a staple of in-home plumbing since the mid-1980s due to their low cost and ease of installment. In the past 20 years, PEX tubing has become increasingly popular in newly built homes across North America.

As noted above, the NSF/ANSI 61 requires a mandatory quality testing for product certification. Thus, the chemical concentrations of the product’s material are evaluated to ensure their use will not contaminate drinking water.


The Department of Licensing and Regulatory Affairs (LARA) and the Bureau of Construction Codes regulate plumbing in the State of Michigan. Additionally, plumbing licensing and registration is now governed by the Skilled Trades Regulation Act (Act 407 of 2016), Article 11, which became effective in April 2017 after the repeal of the State Plumbing Act.

Furthermore, LARA has a Plumbing Division that is principally responsible for administering and enforcing the Michigan Plumbing Code - which is published by the International Code Council - and the plumbing provisions in the Michigan Residential Code.