Water pressure in a home is an important aspect for many home builders. No one likes a faucet or shower head that doesn’t produce ample pressure. There are many factors that can contribute to low water pressure in your home. One factor that doesn’t get enough attention is the impact of plumbing material choices. Copper has been replaced by plastic pipes and fittings in many residential markets due to their ease of installation and lower cost. However, different plastic materials have different performance components that can impact both quality and water pressure.
Fitting That Restrict Flow
Currently, the top two choices in plumbing are Chlorinated PolyVinyl Chloride (CPVC) and cross-linked polyethylene (PEX). The main difference between the two is the type of fitting used. CPVC uses a solvent weld process, similar to copper, to secure full flow fittings to the pipes. This creates minimal drop in water pressure as CPVC can be sized the same as copper. However; PEX uses fittings that are inserted into the pipe causing the internal diameter to be reduced at each fitting. This can disrupt the flow and reduce water pressure. Reduced water pressure is true even though some manufacturers will claim that with expansion fittings, which are 10-20% smaller than the pipe, you will have full flow. The internal diameter of a 1/2″ PEX pipe can be reduced anywhere from 21% to 35% depending on the fitting that you use. This translates to a drop of 2 to 4 psi in water pressure for each 90-degree elbow fitting used in the system. Other fitting types can also create similar reduction and can reduce water pressure at fixtures in your home unless oversized pipes are used.
Water Quality Risks
There has been an increased focus on building “healthier” homes. Quality of water is one area that is getting new attention. A home’s water quality can be affected by plumbing systems in a variety of ways. This includes biofilm formation, permeation and leaching. Biofilms can harbor and promote bacteria growth such as E.coli and legionella in a home’s water supply. Multiple tests have shown that CPVC consistently presents on the lowest biofilm formation potentials and PEX consistently shows a higher potential for biofilm growth.
When chemicals come in contact with the external of a piping system and soak through the pipe wall and enter the water supply it is called permeation. According to information obtained from the EPA, CPVC and other vinyl plastics are “virtually impermeable” at low levels of contamination and will actually fail before allowing the water in the pipes to become contaminated. The EPA study also found that 82% of known permeation incidents occurred with PEX and other polyolefin plastics.
The water quality impacts industry standard is NSF 61. CPVC pipes, fittings and cements are certified to NSF 61 under all conditions. However, copper and some PEX brands have limited NSF 61 certifications depending on either the temperature or pH of the water.
If you have any questions about building your custom dream home in the Hill Country of New Braunfels or have any other questions please reach out to us! We are always available for a consultation and would love to hear from you!