Hose bibs and irrigation supply: the plumbing that lives in the sun

Where plumbing ends and irrigation begins

This is the first thing to settle, because it decides who you should be calling.

The supply side, the pressurized potable water from your meter to the hose bibs, to the point where an irrigation system takes off, and the backflow protection at that junction, is plumbing. It is under mains pressure at all times, it is subject to the same code as the rest of the house, and a leak on it runs on your meter twenty-four hours a day.

The irrigation side, the controller, the zone valves, the drip tubing, the emitters, the sprinkler heads, the scheduling, is landscape irrigation work. It is largely unpressurised between cycles, it is a different trade, and a competent irrigation contractor will do it better and cheaper than a plumber will.

The confusion sits at the junction, and that is exactly where the expensive problems live: the take-off from the potable line, the isolation valve, the backflow device, and the buried supply pipe running to the valve manifold. Water pooling near a valve box could be either side. If it pools when the system is not running. It is on the pressurized side and it is ours.

Hose bibs: why they fail so reliably in Arizona

A hose bib is a simple valve, and outdoors in this state it lives a hard life. Four things work on it at once.

Ultraviolet and heat. Direct sun on a west or south wall degrades rubber and plastic components, and surface temperatures on a sunlit wall in July are far above air temperature. Washers harden, packing dries out, and hose gaskets perish.

Mineral scale. Hard water leaves deposits on the seat and stem, so the washer closes onto a rough surface and wears quickly. It is the same mechanism that shortens cartridge life indoors, but with no relief from a softener because most bibs are plumbed ahead of any treatment.

Mechanical load. A hose left connected, pulled sideways, and yanked round a corner puts leverage on the bib and on the pipe behind it. Loose bibs and cracked interior connections nearly always have a hose history.

Pressure. High static pressure, common statewide, presses on every seal continuously. If bibs and hose gaskets fail repeatedly at your address, measure the pressure before replacing another one; see water pressure regulator.

The failure patterns that follow from this are recognisable. A drip from the spout when closed is a worn washer or seat. Water weeping from around the handle stem when the bib is open is the packing nut or its washer. Water at the wall where the bib enters is more serious, that is either the threaded connection or the pipe inside, and it is putting water into the wall or the slab edge. And a bib that spins loosely in the wall has lost its support and is working the connection behind it.

Repair, rebuild or replace

Most bib faults are cheap. The judgement is whether the body is worth keeping.

A washer and packing rebuild handles a spout drip or a weeping stem on a bib whose body is sound, and it is the least invasive option. On a good-quality brass bib this is worth doing.

Replacement of the bib is the usual answer where the body is corroded, the threads are damaged, the seat is badly pitted, or the unit is a builder-grade item that is not worth rebuilding twice. It is a small job when the bib threads onto an accessible fitting.

Work behind the wall is the case that costs money: a failed connection, a corroded nipple, or a cracked pipe inside the wall cavity or at the slab edge. Signs are water at the wall face rather than the bib, staining inside on the other side of that wall, or a bib that has been moving. This is a repair that has to be opened up and done properly, and there is no version of it that stays cheap if it is ignored, see leak detection if the extent is unclear.

Worth upgrading while it is off: a quarter-turn ball-type bib rather than a compression washer type, which lasts considerably longer against hard water; a bib with a proper anti-siphon device where required; and a solid mounting block or bracket so the next decade of hose-pulling does not go into the pipe.

Buried supply leaks: the ones that cost real money

An underground leak on a pressurized outdoor line is the most expensive plumbing problem people fail to notice, because desert landscaping hides it and evaporation removes the evidence.

The tells: a water bill that has climbed with no change in habits; a patch of unusually vigorous growth or a green area in decomposed granite; damp or dark gravel that never dries; a sinkhole or subsidence in a bed; a hissing sound at a nearby valve box; and the definitive one, the meter continuing to register with every fixture in the house closed and the irrigation controller off.

How to confirm it yourself in ten minutes. Close every tap in the house and switch the irrigation controller off. Read the meter, wait an hour without using water, read it again. Movement means a leak somewhere on your side of the meter. To narrow it further, close the main shutoff at the house: if the meter still moves, the leak is between the meter and the house shutoff, a service line or outdoor supply problem. If it stops, the leak is inside the house envelope.

Locating it precisely is the skilled part: acoustic listening on the pressurized line, isolating and pressure-testing sections, and correlating with visible evidence. That matters because in Arizona ground the digging is the expense. Caliche is cemented and slow, and irrigation runs are often routed under hardscape, decorative rock, mature plantings or a driveway. An accurate location turns a day of trenching into a small hole, the same economics described on main water line repair.

Anti-siphon and backflow devices

Where irrigation, a hose or an outdoor water feature connects to potable supply, there has to be protection preventing water flowing back into the drinking supply. This is one of the genuinely important details outdoors, and it is regularly missing or defeated.

On a hose bib the protection is typically an integral anti-siphon device or an add-on vacuum breaker. On an irrigation take-off it is a larger assembly appropriate to the risk. Devices fail: the internal components perish in the heat, they clog with mineral deposits, and add-on vacuum breakers are frequently removed because they drip once they age.

The reason it matters in this state is practical rather than theoretical. A hose lying in a pool of standing water, a hose end submerged in a spa or a livestock trough, a fertiliser injector on a garden line, combine any of those with a pressure drop on the main and the flow can reverse. That is precisely what these devices exist to stop.

What we do: fit, replace and repair anti-siphon devices, vacuum breakers and the plumbing of a backflow assembly. What we do not do: certification testing of backflow assemblies. That is a separately certified activity, and where your water provider requires annual testing, it must be carried out by a tester on their approved list. We will tell you when your device looks like it needs testing, and we will plumb the assembly correctly, but the test and the paperwork are not ours to sign.

Pressure and flow at the far end of a long run

Arizona lots can be large, and the far hose bib is often a long way from the meter. Complaints about weak outdoor flow usually have one of four causes.

First, distance and diameter, a long run of undersized pipe loses pressure over its length, and adding a bib at the end of a line that was already marginal produces a disappointing result. Second, scale inside older galvanized outdoor piping, which narrows the bore substantially over decades. Third, a partially closed or failing isolation valve somewhere in the run, which is common and easily missed. Fourth, a whole-house pressure problem that happens to be most obvious at the furthest point.

The diagnostic is straightforward: gauge the pressure at a bib close to the meter and at the distant one. A big difference points at the run; a similar low reading at both points at the supply or the regulator.

It is worth adding that outdoor demand is where Arizona homes use most of their water. Poor flow at a distant bib often coexists with an irrigation system that has never had the pressure it was designed for, which is why the fix sometimes belongs on the supply side rather than in the landscape.

Adding or moving a hose bib

A new bib in a sensible place is one of the more satisfying small jobs on a property. What decides the cost is where the nearest usable supply is, not the bib itself.

Typical cases: a bib on the far side of a house so a hose reaches; a dedicated bib at a garden or vegetable bed; a supply point at a casita, workshop or RV pad; and a frost-protected bib in high-country properties. Each needs a route, and the route is either through a wall cavity, along an exterior wall, or buried.

Details worth insisting on: an accessible isolation valve so the new bib can be shut off without closing the whole house; the correct anti-siphon device; a proper mounting so the bib is supported rather than cantilevered on the pipe; and sensible protection where a line runs above grade in the sun.

If the goal is to feed an irrigation manifold or a future feature, say so up front, a bib sized for a hose is not the same as a supply point for a zone valve manifold, and putting the right diameter in the ground the first time costs very little more.

Freeze protection, where it genuinely applies

Statewide advice about outdoor faucets does not fit this state, because Arizona has several climates.

In the low desert. Phoenix, Tucson, the Pinal corridor, the western river towns, hard freezes are infrequent and short. Outdoor plumbing there is far more threatened by UV and heat than by ice, and the sensible precautions are shade, protection and quality fittings.

Above roughly four thousand feet. Prescott, Sedona, Flagstaff’s neighbors, the White Mountains, Chino Valley, Show Low country, freezing is a real annual event and outdoor plumbing needs to be treated accordingly: frost-proof bibs, insulation, and disconnecting hoses in autumn. A hose left connected over a freezing night traps water against the bib and is the single most common cause of a burst outdoor connection anywhere that gets cold.

Even in the low desert, a handful of nights each winter reach freezing, particularly in outlying areas. Disconnecting hoses and covering exposed bibs on those nights is cheap insurance, and it is far less work than a burst pipe repair.

Long absences and outdoor water

A leaking outdoor line at an occupied house gets found by a bill. At a seasonal property it can run all summer.

That is why outdoor supply belongs in any closing-up routine: shut the main, or at minimum isolate the outdoor supply and irrigation take-off; check the meter afterwards to confirm nothing is moving; and know who is looking at the property while you are away. Where the landscape needs watering through the summer, the irrigation supply has to stay live, which means the rest of the house should be isolated separately rather than leaving everything on. That is one of the more valuable things to get right, and it is covered on vacant home water shutoff and prep.

One last point for anyone who has just bought a property here: find your outdoor isolation valves and confirm they actually turn. Valves that have sat untouched for a decade in this soil frequently do not, and discovering that during a leak is the wrong time.