Hot Water Recirculation in Norwalk, CA

A short provision in the city's water code quietly governs every added dwelling here, and almost no one meets it until the drawings are done.

It says that every house or building under separate ownership receiving domestic service shall be provided with a separate service connection. Two or more buildings under one ownership on the same lot may share a single connection, subject to the City's limits. A connection may not supply property under single ownership located on opposite sides of a public street or alley, and it may not supply adjoining property of a different owner.

Read that against what people actually build. An accessory unit behind the house, on the same lot and under the same ownership, sits squarely within the shared-connection permission. A unit created by splitting the lot, or intended to be sold separately, does not need a service of its own.

The code even settles what happens on a split. Where a parcel is divided, the existing service connection is deemed to be assigned to the lot nearest the meter or service terminus. So, the question of who retains the original service is not a matter of negotiation. It has an answer.

The two arrangements produce entirely different hot water geometry, and therefore two different quotes, decided by a paragraph in the water code. Which is why a quote here is written after that paragraph has been applied to your lot, with the case we assumed named on the page you are handed.

All of which is checkable against your own lot before anybody quotes anything, and it is the reason the order of this visit runs the way it does.

A shared service usually includes a shared heater, which redistributes hot water across the property. A dwelling at the back of a lot lands at the end of the longest run, so the worst wait in the building gets worse for both households. The front of the house feels it too, since a loop installed for the rear unit changes what every faucet upstream of it does. None of this argues against sharing a service. It argues for knowing which arrangement you are in before anybody designs around it.

The second effect applies to the heater rather than the pipe, and a surprising number of quotes omit it. Two households draw at overlapping hours, so a tank is asked for more volume inside one window and given less time to recover between demands. A loop then adds a standing thermal load on top, because circulating water sheds heat the whole way round and comes back wanting reheating. Fitted to a heater already at its limit, a loop delivers hot water sooner and runs out of it sooner. Put in those words, few people would choose that trade. So the heater gets a finding of its own on our paperwork, and you decide with both in front of you.

The third point is the one to carry away. When the service question puts the added dwelling on its own connection and heater, runs stay short at both buildings and the problem a loop solves may never appear. Sometimes the best recirculation system is the one the geometry made unnecessary.