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posted: 3/5/2017 6:00 AM

Dispute over water pressure divides buyers, seller

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Q. As a licensed engineer, I take exception to the findings of the home inspector who just evaluated my home. According to the inspection report, the water pressure in my plumbing system is 90 pounds per square inch (psi), supposedly 10 pounds above the legal limit. Based upon this finding, the buyer insists that I install a pressure regulator. However, the inspector failed to notice the pressure relief valve in the main water line is rated at 150 psi. This means my plumbing system can withstand pressures well in excess of 90 psi. Home inspectors should pay closer attention to the homes they inspect before disclosing problems that may not actually exist. How can I convince the buyer and inspector that a regulator is not needed?

A. The buyers and their home inspector are not the ones who need convincing. According to basic standards of the plumbing code, water pressure in a residential plumbing system may not exceed 80 psi. When the incoming service pressure exceeds 80 psi, a regulator is required to restrict the pressure level.

The code does not provide exceptions to the maximum water pressure limit because fixtures and appliances are not designed to withstand higher pressures. The fact that someone installed a 150 psi relief valve in your main water line does not alter or elevate the characteristics of your plumbing system.

Standard plumbing components have physical limitations. They can withstand just so much pressure. When these levels exceed 80 psi, damage or leakage may occur. For example, the connections in washing machines consist of rubber hoses clamped to plastic fittings: not nearly as strong as a solid pipe connection. If one of these attachments should break or disconnect due to excess pressure, the result could be major water damage inside the home.

Your 150 psi relief valve protects the system from pressures above 150 pounds, but it does not protect your fragile plumbing from pressures between 80 and 150 pounds. My advice is to follow the inspector's recommendation. A pressure regulator is cheap insurance for the protection is provides.

Q. Our deck is attached to the house and is also touching the soil. The people who are buying our home want us to eliminate the earth-to-wood contact. They think it can adversely affect the house, in spite of our assurances to the contrary. We've explained that the deck can't effect the building because the walls are covered with stucco. How can we make them understand that their concerns are unwarranted?

A. The sale of your home will probably involve the services of a pest control operator, commonly known as a termite inspector. The job of the pest inspector will be to determine whether earth-to-wood contact at the deck is likely to effect the house. If the deck adjoins the building at stucco surfaces only, resultant damage to the house is unlikely. However, be sure to consider whether the deck connects to any of the wood trim. That could shed a different light on the matter.

• To write to Barry Stone, visit him on the web at, or write AMG, 1776 Jami Lee Court, Suite 218, San Luis Obispo, CA 94301.

© 2017, Action Coast Publishing

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