Partial repipes were common. The visible run got upgraded and the branch lines did not. If pressure is fine at the kitchen and poor at the back bathroom, that is the pattern.

This is most common in homes built roughly 1940 to 1980. Post-war and mid-century — copper supply, aging cast iron stacks, 60 to 100 amp panels, first-generation central air.

Related

• Pressure drops at every fixture at once
• Every drain in the house is slow, not just one
• Rusty water only on the first draw
• The main shutoff will not turn
• Sewer backs up in the lowest fixture after heavy rain
• Sewer smell from a room nobody uses
• Hose bib with no vacuum breaker
• Stain on the ceiling directly under a bath

Back to Plumbing.

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Written by Jaylan Jones. I Like To Fix earns a referral fee when a call connects to a contractor. See our business-model disclosure.