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Types of leaks in water supply or drain piping:
This article describes the different types of plumbing leaks that can occur in building supply piping or drain piping.
Knowing just what kind of leak is occurring in a building helps pinpoint the problem and also helps specify the necessary plumbing repair.
We discuss: Water supply pipe and well pipe leak types & diagnosis. Types of plumbing leaks helps find leaks in buildings. When where, why, and how to check for & fix water supply and drain leaks. How to de-winterize a building and restore the plumbing & heating systems to service
Watch out: a water supply leak, left un-attended, can cause catastrophic damage to a building, wetting floors, walls, ceilings, even filling a basement such as could have happened to the flood-damaged home in the photo above.
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Types of Water Supply & Drain Pipe Leaks - How to Find Plumbing Leaks in buildings
Understanding the types of water leaks that occur in building piping can help you find or watch out for leaks that are not so obvious when water is first turned on in a building. Keep in mind that these are by no means all of the building leaks that can occur.
Others include leaky shower pans, leaky air conditioning condensate drains, bad sump pump drains, leaky water tanks, leaky water heaters, leaks at tankless coils, and leaks from outside the building from roof runoff or surface runoff. Here we describe the differen ttypes leaks that occur in building piping.
Understanding what's going on with a pipe leak can help avoid making matters worse as well as help directing the repair.
The water seeping from the paster wall shown at left was a leak that could teach us about water supply piping leaks and repairs: water was just seeping out of the wall until someone got curious and "poked" the wall to make a larger hole.
Then water came spewing out of the wall from a burst main water supply pipe connected to municipal water.
Don't do that! Fortunately someone had the presence of mind to jam a stick into the hole to reduce the rate at which the buildig was flooding. Details of this hullabaloo and how it was repaired are at REPAIR BURST LEAKY PIPES.
Gusher water supply pipe water leaks: if a water supply pipe has burst, split, been cut open, or has separated at a solder joint, as soon as water is turned on to that area of the building the pipe will probably leak a lot of water very quickly: you will notice gusher leaks almost immediately by sound or by the visual evidence of water flooding or wetting some area of the building.
Drip and pinhole water supply pipe leaks - Corrosion: a small leak may be present at a water supply pipe such as from a loose threaded fitting, worn valve stem packing, or even a pinhole due to corrosion or due to a nail or screw having been driven into a supply pipe. These leaks can take a longer time to discover because the rate of leak is so slow.
(Don't pull out that nail or screw when you find it until you've first shut off the water supply or a bigger leak will ensue
But these leaks normally are indeed discovered in days or weeks after they occur.
Plumbing Fitting Leaks - can occur if a fitting, coupling or union for example, is not properly soldered, tightened or if a threaded fitting was installed without proper seralant.
We also find leaks at plumbing supply pipe connections and fittings when dis-similar metals are joined without a diaelectric fitting. See DIELECTRIC FITTING CODES
Types of Leaks in Building Drain Piping
Plumbing drain leaks: plumbing drain leaks are a bit like our hidden water faucet leak: they only show up if the particular leaky drain is carrying wastewater.
For example, a leaky shower trap in an upstairs shower may go unnoticed for a long time if it's the guest-bath shower that is rarely used.
Except where the drain pipes are visible, such as in a basement or crawl space, plumbing drain leaks may be slow to appear and show up as a stain in a ceiling or wall below the offending drain, or as mold or mold odors in a building.
Of course if a plumbing drain has literally burst or fallen open the leak will be enormous and will show up quickly as was the case with our gusher water pipe leaks described above.
Sink basin or sink strainer leaks: leaks also occur at the drain assembly of all types of sinks due to improper installation, loose parts, missing gaskets or sealant, or from corrosion.
Watch out: a corroded leaky sink strainer or sink stopper assembly can leak sending water down the exterior of the drain piping where it may be mistaken for a drain pipe leak.
Bath tub or sink overflow leaks: these fixtures can overflow into the building if water if the fixture drain is closed and the fixture is left unattended. Modern sinks and tubs include an overflow opening that is designed to send water into the fixture drain system if the fixture water level is too high.
Some older plumbing fixtures lack this feature and have no overflow provision.
On occasion we find that even though the fixture has an overflow drain opening, that opening is blocked, or in the case of bath tubs, the overflow drain was never properly connected to the tub drain system.
The photo above shows a bathtub overflow fitting from the wall cavity side. We cut this opening to permit repairs after water from the bath tub appeared in the ceiling of the room below.
We found two leaks:
Episodic leaks at the bath tub occurred when the bath tub was filled to the height of the overflow (or when shower water splashed around the overflow). The gasket had long dried out and was dislocated. Click to enlarge the photo and you'll see leak stains on the tub surface.
Every-use leaks at the bath tub: The second leak was due to loose trap fittings below the bath tub.
Faucet leaks: sink, tub, shower, or laundry sink faucets may leak continuously by dripping into the fixture sending that water down the drain system. But such leaks can still cause problems by flooding a septic system (in severe cases) or by causing freeze damage to drain pipes in cold climates.
A visible water faucet leak is one that shows up where you can see it, such as dripping into the sink, tub, or shower around the faucet control when the control is opened, but stopping when the faucet is shut. Or the faucet may drip continuously because the faucet washer or the base against which the washer seals has been damaged or is worn-out.
A hidden water faucet leak is much more sneaky. Particularly at tub and shower controls mounted on a vertical wall, some faucets may leak inside of the wall cavity when the faucet is open and water is running. Because these leaks are usually just a slow drip, the leak may be present for months or even longer before it is finally noticed
Typically these surreptitious faucet leaks show up as a stain in a ceiling below the fixture or as mold or moldy odors in a building. Opening a wall or ceiling cavity may be necessary to find and repair such leaks.
A more odious faucet leak can occur when the faucet valve stem packing fails.
Plumbing fixture control valve stem leaks: sometimes a sink, tub, or shower faucet develops a leak, usually around the valve stem packing, that will leak only when the valve is in the open position - that is, when water is running at that faucet. These leaks fall in two sub-classes: visible and hidden.
Faucet valve stem leaks at a bath, kitchen or laundry sink can send water across the fixture top surface, onto counters, into cabinets, onto or into floors.
A similar odious tub or shower control leak can send water dripping into the wall or floor cavity.
Loose toilet base leaks: toilet may wobble on its base which is a sure sign that it's going to leak into the floor when the toilet is flushed.
But even a toilet that doesn't wobble may leak into the floor if the wax ring seal between toilet and drain pipe is missing or improperly installed.
These leaks will accumulate on the floor or below the floor, appearing perhaps also on the ceiling below. They occur each time the toilet is flushed, or they may be continuous if the toilet is running.
Well pipe leaks can be tricky to find as the pipe is usually buried for most or even all of its course between well and building. However there are symptoms that can point to a well pipe leak.
Water will leak out of a well pipe at a bad connection, perforation, or cracked pipe when the well pump is running, particularly if the water system uses a submersible pump that is located in the well itself.
If you have this problem you may find a wet spot in the ground near the well piping, provided that the pipe is close enough to the surface.
You will also notice that the well pump is running more often than normal, and that your "apparent" water usage may have increased. Some people even report finding a "water fountain" or geyser in the lawn at a burst water supply pipe from both private wells and from a municipal water main.
Air may leak into a well water pipe at a bad connection, perforation, or other damage when the well pump stops running, particularly if the leak problem is combined with a defective check valve or foot valve in the piping system.
The result may be air discharged from plumbing fixtures (see AIR DISCHARGE at FAUCETS, FIXTURES), improper air charge in the water pressure tank, or loss of pump prime. Short cycling of the water pump or loss of pump prime may result as well.
At WATER PRESSURE PROBLEM DIAGNOSIS TABLE we note that a possible explanation for loss of building water pressure, or loss of well pump prime can be air leaking into a well piping line, as well as water leaking out of the well pipe.
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"New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: email@example.com
"Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
"How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
Thanks to reader Dan Babb for discussing well piping leaks, July 2010
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