Chapter 6 Key Takeaways: Your Home's Water Supply

The Single Most Important Action

Find and test your main shutoff valve today. Before you need it in an emergency, locate the valve that stops all water flow into your house, confirm it operates freely, and tell every adult in the household where it is. This five-minute task can prevent thousands of dollars in water damage.


The Municipal System

  • Your utility delivers treated, pressurized water to your meter. Everything from the meter into the house is your responsibility.
  • The service line from the meter to the house is typically your responsibility, even the section under your yard.
  • Annual water quality reports (Consumer Confidence Reports) are publicly available from your utility and tell you exactly what's in your water.

Pipe Materials: What They Mean

Material Key fact Action if present
Galvanized steel Corrodes from inside; over 50 years old, likely severely restricted Budget for repiping; check for localized sections even if mainly copper
Copper (pre-1986) Lead solder at joints may leach Test tap water for lead; flush 30–60 sec before drinking
Copper (post-1986) Excellent; watch for pinhole corrosion in high-chloramine water Inspect joints annually for green staining
CPVC Good track record; becomes brittle with age Handle carefully during renovation work in older homes
PEX Modern standard; flexible and freeze-resistant No special concern; verify NSF 61 certification

Water Pressure: The Numbers

  • Normal range: 40–80 PSI
  • Ideal: 60 PSI
  • Below 40 PSI: Investigate PRV failure, pipe restriction, municipal supply
  • Above 80 PSI: High risk of fixture and appliance damage; install PRV
  • How to test: $10–$20 gauge on any hose bib or washing machine connection

Common Pressure Problem Sources (Check in Order)

  1. Municipal supply (call utility, check with neighbor)
  2. Pressure reducing valve failing (open or closed)
  3. Galvanized pipe corrosion narrowing pipes
  4. Partially closed main shutoff
  5. Clogged aerators or showerheads (single fixture only)

Protective Devices

Pressure Reducing Valve (PRV): - Steps down high municipal pressure to safe levels - Required if incoming pressure exceeds 80 PSI - Lifespan: 10–20 years; replace when pressure deviates from setpoint - Cost to install: $200–$400

Expansion Tank: - Required in any closed system (one with a backflow preventer) - Absorbs pressure from thermal expansion of heated water - Air charge should be checked every 1–3 years - Cost installed: $150–$350; check air charge annually yourself


Well Systems (Private Water Supply)

The pressure tank: Stores water between pump cycles; the air bladder maintains pressure. Bladder failure causes short-cycling (pump runs every few seconds). Check with a magnet test (hollow section should sound different from water-filled sections) and Schrader valve test.

The pump: Submersible pumps last 15–25 years. They fail by motor burnout, worn impellers, or failed check valves. Never let a well pump run dry.

Annual well maintenance checklist: - Test water: bacteria, nitrates, pH at minimum - Inspect wellhead for physical integrity - Check pressure tank air charge - Listen for abnormal cycling patterns

Well owner mantra: You are the utility. Test the water, inspect the equipment, and know your system.


Water Quality Essentials

  • Hard water (above 7 GPG / 120 mg/L): Common in 85% of U.S. homes; causes scale in pipes and appliances; not a health risk but expensive if untreated
  • Lead: Test your tap water if home was built/plumbed before 1986
  • Well water: Test annually; county health departments often offer free testing
  • Filter to the problem: Get a water test first; then choose a filter rated by NSF for your specific contaminants

Cost Reference

Item Typical Cost Range
Water pressure gauge $10–$20
Replace gate valve with ball valve (main shutoff) $150–$300
Replace fixture shutoff valves (per valve) $80–$150
Install pressure reducing valve $200–$400
Install expansion tank $150–$350
Whole-house repiping (galvanized to PEX or copper) $4,000–$15,000
Replace well pressure tank (professional) $500–$1,200
Replace submersible well pump (professional) $1,500–$3,000
Basic water quality test (lab) $100–$300