Winter Watering Rules and the Clock Change: A 15-Minute Plumbing Check for Las Vegas Homes

Two things happen at the start of November in Las Vegas, and they arrive together. The Southern Nevada Water Authority moves the valley to its winter watering schedule, one assigned day per week instead of three. And daylight saving time ends on the first Sunday of November, which is the moment most people finally walk out to the irrigation clock. That trip is worth more than a schedule change. It is the cheapest fifteen minutes you will spend on your plumbing all year, because everything you check at that clock is a place where water can get in, freeze, or leak undetected for months.

What Actually Changes on November 1

Las Vegas runs on a seasonal watering schedule, and the rules are mandatory, not a suggestion. Through the end of October the limit is three assigned days per week. Starting November 1 it drops to one assigned day per week and stays there through the end of February. Sprinkler watering on Sunday is prohibited in every season, so Sunday is never your day no matter what group you are in.

Your day is set by a watering group, labeled A through F, and each letter maps to a weekday. Group A waters Monday, B Tuesday, C Wednesday, D Thursday, E Friday, and F Saturday. You can look the group up on the SNWA site or find it printed on your monthly water bill. If you run sprinklers outside your assigned day, that counts as water waste and can bring a fee or a citation, which is a genuinely avoidable bill.

The rules also cover drip irrigation, not just sprinklers. Drip delivers water more slowly, so it should run longer and less often than a sprinkler zone. If you have converted parts of your yard to drip, your winter schedule applies there too, and it is worth reading the emitter flow rate before you decide the runtime.

Why the Clock Change Is a Plumbing Task, Not Just a Chore

Changing the time on an irrigation clock is the smallest part of it. The bigger reason to go out there is that November is the month your outdoor plumbing stops being boring. Overnight temperatures in the valley do dip toward freezing in the winter months, and the parts of your system most exposed to that cold are exactly the parts you are standing next to: the backflow assembly, the hose bibs, the valve box, and any hose left connected.

Water expands when it freezes. A hose still threaded onto a spigot gives that expansion nowhere to go, so the pressure backs up into the pipe behind the wall. A backflow assembly sitting above ground with water trapped inside it can crack the same way. These failures are quiet, and you usually find out in February when you turn the system back on and water comes out of the side of the device instead of the sprinklers. Fifteen minutes in November is the difference between finding that now and finding it in spring.

The 15-Minute Check, in Order

Work through these at the irrigation clock and the side of the house. Nothing here needs a tool beyond a screwdriver and a rag.

1. Set the Clock to Your Winter Day

Reset the schedule to your one assigned day and confirm Sunday is off. Then reset the actual time, because daylight saving time is ending and the clock is now an hour off. A smart controller handles the time change itself and many water utilities offer a rebate for one, but the winter day still has to be set correctly either way. If your controller has a seasonal adjust or budget percentage, dropping it for winter saves water without rewriting every zone.

2. Look at the Backflow Assembly

The backflow preventer is the brass fitting between the water supply and your irrigation system, and it exists to stop irrigation water from ever flowing back into the drinking supply. In Las Vegas it is a testable device, and that test has to be done on a schedule by a certified tester. Winter is when a cracked body or a bell housing full of water becomes obvious. Look for water weeping from the ports, a bent or missing test cock cap, and any sign the device was left holding water. If it failed or was never tested, this is the season to deal with it rather than the spring rush.

3. Disconnect Every Hose

Take the hose off the spigot. All of them, including the one behind the garage that you forgot about. Drain the hose and store it. A connected hose is the single most common cause of a split pipe behind an exterior wall, because it traps water against the valve with nowhere to expand.

4. Shut Off and Drain What You Are Not Using

If you have a separate irrigation shutoff valve, this is a good time to think about whether you want the whole system off for the season. Many valley homeowners keep watering one day a week through the winter, which is fine and often better for the landscape. But pool fill lines, evaporative cooler lines, and any hose bib on a dedicated run that you will not touch until spring can be shut off and drained. Know where your main shutoff is while you are out there, and make sure the handle actually turns. A shutoff that has seized is a shutoff you do not have in an emergency.

5. Walk the Valve Boxes and Look for Wet Spots

Before you close the lid, look inside each valve box. Standing water in a valve box in November usually means a valve is weeping or a fitting is loose, and that leak will run quietly all winter under a lid nobody opens. The same goes for the yard: a permanently wet patch, a strip of greener grass along a run, or a dip in the lawn can be a buried line leaking. Winter is the easiest time to spot these, because nothing else is watering the yard.

Why This Matters More in a Hard Water Valley

Las Vegas water is among the hardest in the country, and that changes how your plumbing ages. The dissolved minerals that leave scale on shower doors also build up inside valve bodies, backflow assemblies, and water heater tanks. Scale narrows passages and stiffens the parts that are supposed to move, so a valve that would last years in softer water can seize or start weeping sooner here. Winter is when that wear shows up, because the system sits idle and small leaks have months to do damage without anyone noticing.

If you are already thinking about the water, the same trip outside is a reasonable time to look at your water heater. Sediment settles in the tank over the year, and a heater that has never been flushed in a hard water valley is working harder than it needs to. It is not an emergency, but it is the kind of thing worth putting on the list before the first cold snap rather than during it.

What to Do If You Find a Problem

Most of what you find on this walk is small: a hose to disconnect, a clock to reset, a valve to tighten. Some of it is not. A cracked backflow assembly, a shutoff that will not close, water standing in a valve box, or a wet spot that will not dry are all worth a professional look, and they are much cheaper to fix in November than after a freeze or a water bill spike.

Kingdom Plumbing is a family-owned Las Vegas company serving the valley since 2018, with three Las Vegas offices and two more in Henderson, and a real person answering the phone around the clock. We are licensed under NV Contractors License #0085422, rated 4.9 stars across 615 reviews, and every job comes with a flat-rate quote you approve before any work starts. Call (702) 840-5037 if you want a second set of eyes on the backflow assembly, the shutoff, or anything else you found out there.

Learn more about backflow testing in Las Vegas, or read about leak detection and repair if you found a wet spot you cannot explain.