Key Takeaways
- Your main shutoff is usually where the water line enters the house — basement front wall, crawl space, utility closet, or near the water heater.
- Ball valve (lever): parallel = open, perpendicular = closed. Gate valve (round wheel): turn clockwise until it stops.
- After shutting off: open the highest faucet first to break vacuum, then drain from the lowest — and protect the water heater (electric → breaker off; gas → pilot).
- Vacation rule: gone more than a couple of days in winter? Shut the main off. It’s the cheapest flood insurance there is.
- The curb stop at the street belongs to the utility — you need a curb key and, in most jurisdictions, permission to touch it.
Where Is My Main Water Shut-Off Valve?
Follow the line in: the main shutoff sits where water enters your house — most often the basement front wall, a crawl space, a utility closet, or near the water heater.
The meter-to-wall trick: find your water meter first (ground box near the curb or sidewalk). The service line runs in a straight line from the meter to your house — walk that line to the foundation wall and look inside at that spot. The valve is usually within 3–5 feet of where the line penetrates the wall.
First valve wins: the first valve on the line inside your house is the main. Everything downstream — branch valves to bathrooms, the kitchen, hose bibs — controls individual areas. In an emergency, always go for the main first.
What Kind of Shut-Off Valve Do I Have?
| Valve | How it looks | How to close it |
|---|---|---|
| Ball valve | Single lever handle | Turn 90° so the handle is perpendicular to the pipe |
| Gate valve | Round wheel handle | Turn clockwise until it stops (several turns) |
| Curb stop | Buried at the street, needs a key | Don’t — utility property in most areas |
Ball valves beat gate valves — one quarter-turn vs. many, and they rarely seize. If your main is an old gate valve that hasn’t moved in a decade, consider having a plumber replace it with a ball valve before the emergency. A seized main valve discovered during a burst pipe is a nightmare.
How Do I Shut Off the Water and Drain the Pipes?
Close the main, then drain: highest faucet first (breaks the vacuum), lowest faucet last.
- Close the main valve (perpendicular for ball, clockwise-stopped for gate).
- Protect the water heater FIRST: electric → flip its breaker OFF (elements burn out in minutes without water). Gas → set to pilot (not off — relighting is a hassle; pilot keeps it safe).
- Open the highest faucet in the house (upstairs bathroom) — hot and cold. This breaks the vacuum so water can drain.
- Open the lowest faucet (basement laundry tub or outdoor hose bib) and let the system drain.
- Flush toilets to empty tanks.
- The bathtub test: run the tub — when it goes from stream to dribble to nothing, the system is drained. If it never stops, your main valve isn’t fully closing (see below).
Reopening: close all faucets first, then open the main slowly — a fast-opening valve hammers the system (see our water hammer guide). Let air sputter out of each faucet before calling it done.
What If My Main Valve Won’t Turn?
Don’t force it — a snapped valve stem turns a shutoff attempt into an emergency.
- Gate valve stuck: try gentle back-and-forth pressure, not brute force. Penetrating oil on the stem, wait 15 minutes, try again.
- Still stuck: stop. Call a plumber — replacing a seized main valve is routine work and far cheaper than the flood from a broken one.
- No main valve at all? Some older Denver homes only have the curb stop at the street. You’ll need a curb key (a long T-handled tool, ~$20 at hardware stores) — but check local rules first: in many jurisdictions the curb stop is utility property and operating it yourself can bring a fine. When in doubt, call the water utility or a licensed plumber.
Should I Shut Off Water When Going on Vacation?
Yes — for any trip longer than a couple of days, especially October through April. A burst pipe on day two of a ten-day trip runs undetected the whole time. Shutting off takes two minutes:
- Close the main valve.
- Drain per the procedure above (or at minimum, open the lowest faucet).
- Set the thermostat no lower than 55°F.
- Water heater to pilot (gas) or breaker off (electric).
For the full winter protocol, see our winter plumbing tips.
Fixture Shutoffs: Stop the Problem Without Killing the Whole House
Every fixture should have its own shutoff — use these for isolated issues:
- Toilet: oval-handled valve on the wall behind it (clockwise to close).
- Sink: two small valves under the basin (hot left, cold right).
- Washing machine: red/blue lever valves behind the unit — close these when the machine isn’t running; burst washer hoses are a top flood cause.
- Water heater: cold-inlet valve on top of the tank.
- Hose bibs: interior shutoff + drain the line before winter.
If a fixture has no shutoff valve (common in older homes), that’s a small upgrade worth making — it turns future repairs from whole-house shutdowns into five-minute jobs.
Smart Shut-Off Valves: Worth It?
Whole-house smart valves (like Flo by Moen or Phyn) monitor flow 24/7 and auto-close on detecting abnormal usage — a burst pipe at 2 AM gets stopped in minutes, not days.
Worth considering if you: travel frequently or own a second home; have a finished basement (where water damage is most expensive); want the insurance discount many carriers offer for leak-detection systems.
They install on the main line (a plumber’s job, ~1–2 hours) and pair with phone alerts. Not a replacement for knowing where your manual main is — it’s a backup for when you’re not home to turn it.
Build a 5-Minute Emergency Shutoff Kit
Keep these together under the kitchen sink or by the main valve: Curb key (if your jurisdiction allows homeowner use); Channel-lock pliers (for stubborn slip nuts); Flashlight (valves hide in dark corners); The water utility’s emergency number taped inside a cabinet door; Our number: (720) 390-2652 — 24/7.
Frequently Asked Questions
How do I know if my main water valve is open or closed?
Ball valve: handle parallel to the pipe = open, perpendicular = closed. Gate valve: turn counterclockwise to open — if it spins freely with no resistance change, it may be broken internally.
Can I shut off water to just one bathroom?
Yes, if it has branch shutoffs — look for valves on the supply lines under each sink and behind the toilet. No branch valves? You’ll need the main.
How long does it take to drain house pipes?
15–30 minutes for most homes once faucets are open. Larger homes with long runs take longer — wait for the bathtub test to confirm.
Will shutting off water damage my water heater?
Only if you skip the protection step. Electric heaters burn out elements within minutes of dry-firing — breaker OFF first. Gas units go to pilot. Tankless units: power off.
Who do I call if the curb stop is broken?
Your water utility — the curb stop and service line to the meter are typically their responsibility. Don’t excavate it yourself.
Can’t find your main valve, or is it seized? Professional Plumbers Denver locates, frees, and replaces main shutoffs across the metro — and we’ll label everything while we’re there. Call (720) 390-2652, 24/7.
