Plumbing hub

Cold plunge plumbing: make the water loop easy to flow and easy to service

Plumbing is where a correct chiller and pump can become an unreliable system. Reduce restriction, design for filter service and verify operating flow.

ChillSizer technical guideUpdated Aug 2026Physics-first
Quick answer

Good plumbing preserves pump head, protects chiller flow and lets you service equipment without draining the tub.

Baseline plumbing diagram

TUBcold water reservoir PUMPafter isolation valve FILTERserviceable housing CHILLERmin-flow gate Return line to tub · keep hose diameter large · add unions/isolation valves for service

Baseline loop. UV, ozone, bypasses and heaters change placement; always follow the equipment manufacturer’s required orientation and electrical instructions.

Four plumbing principles

  1. Keep suction short and unrestricted.
  2. Use enough diameter for the target flow.
  3. Put unions/isolation valves around serviceable equipment.
  4. Design with dirty-filter restriction, not only a clean loop.

Detailed resources

Frequently asked questions

What is the best cold plunge plumbing layout?

A common baseline is tub → pump → filter → chiller → return, but exact manufacturer instructions take priority.

Is 1-inch hose better than 3/4-inch?

At the same flow, larger diameter usually reduces friction loss, but fittings and equipment connections still matter.

Do elbows matter?

Yes, but hose/pipe diameter and restrictive inline components often dominate. Model the complete loop.

What to read next

Run your exact setup

Use your real tub volume, temperature target, climate, pump, filter and plumbing. ChillSizer checks thermal capacity and actual modeled flow together.

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