The short answer
What a Flare Fitting Does
Flare fittings create a watertight connection for copper water supply lines, most often for appliances like refrigerators or dishwashers. The end of the copper tube is flared outward, and a brass nut compresses this flare against a matching conical seat on the fitting. This metal to metal seal is designed to hold under pressure without gaskets. The quality of the flare and the tightness of the nut are critical for the seal's integrity.
Common Causes of Flare Fitting Leaks
Several installation errors can cause a flare fitting to leak. An improperly made flare, which is cracked, uneven, or too shallow, will not seal correctly against the fitting's seat. Over-tightening the brass nut can crack the flare or distort the tubing. Conversely, a nut that is too loose fails to compress the flare enough, allowing water to seep through. Cross-threading the nut during installation also ruins the seal.
Physical damage to the copper tubing near the fitting is another common culprit. If the tube is kinked or bent sharply, it can stress the flare and break the seal. Corrosion from mineral deposits or a chemical reaction between dissimilar metals can also eat away at the brass or copper over many years. Vibration from an appliance can gradually loosen a nut that was not quite tight enough.
- An imperfect or cracked flare on the tubing end.
- An under-tightened or over-tightened brass compression nut.
- A cross-threaded nut that does not seat properly.
- Physical damage like a kink or bend in the copper line.
- Corrosion from water minerals or galvanic reaction.
- Vibration from appliances slowly loosening the connection.
How to Identify a Leaking Fitting
Look for signs of moisture around the brass nut and the tubing. You might see a slow drip, a constant bead of water, or mineral stains. Feel around the fitting with a dry paper towel to check for dampness. Sometimes the leak is so slow it evaporates, leaving only a white or greenish crust of mineral deposits. This crust indicates a past or ongoing seepage issue.
Listen for a faint hissing sound near the appliance water line, which can signal a pressurized leak. Check for unexplained water pooling under an appliance or inside a cabinet. A musty smell in the area can also point to hidden moisture from a small, persistent leak.
Immediate Steps When You Find a Leak
First, shut off the water supply to that specific appliance or line. Locate the small shutoff valve, usually under the sink or behind the appliance, and turn it clockwise until it stops. If there is no local valve, you may need to turn off your home's main water supply. This stops the flow and prevents further water damage while you assess the situation. Place a bucket or towels under the leak to catch any remaining drips.
Once the water is off, dry the area thoroughly with towels. Move any items away from the wet spot. Do not attempt to re-tighten a leaking flare fitting while it is under water pressure, as this can worsen the damage. If you are not comfortable making the repair yourself, this is the point to contact local water damage pros for leak detection and to address any moisture that has spread.
Repairing or Replacing a Faulty Fitting
For a DIY repair, you must cut off the water, drain the line, and completely disassemble the fitting. You will likely need to cut off the old flare and create a new one using a flaring tool kit. This requires care to make a proper flare. Then, reassemble the new flare, nut, and fitting, tightening the nut firmly but not excessively with two wrenches to avoid twisting the tubing.
Often, it is more reliable to replace the entire section of tubing with a new, pre-flared appliance connector from a hardware store. This ensures a factory perfect flare. If the leak has caused water to soak into walls, floors, or subflooring, the repair goes beyond the pipe. Local water damage pros can perform moisture mapping and structural drying to prevent mold and rot from setting in.
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Call Now (208) 537-2633Frequently asked questions
Can I just tighten the nut to stop the leak?
Sometimes a slight, careful tightening with two wrenches can stop a seepage leak, if the flare itself is still good. But if the flare is cracked or the leak persists, tightening further can make it worse. It is often better to replace the fitting entirely to ensure a lasting repair.
How much does it cost to fix a flare fitting leak?
The cost to repair the fitting itself is often low if it is a simple DIY part replacement. If you hire a plumber, the service call fee applies. The larger cost depends on any water damage caused, which requires mitigation. The final cost depends on the extent of the leak and needed drying.
Will my homeowners insurance cover the water damage?
Coverage depends on the cause and your specific policy. Sudden, accidental leaks may be covered, while damage from long term wear and tear often is not. You must file a claim and your insurer will investigate. Policies vary, and your insurer decides what is covered.