What is that drain pipe on the outside of my house?

Author: Julien Schneider IV  |  Last update: Saturday, September 27, 2025

The two most common drain pipes that most people have on the side of their house are: Air conditioner condensate lines (AC drain line). Water heater pressure relief valve lines (PRV drain line).

Why is water coming out of a pipe on the outside of my house?

If you've noticed a pipe leading to the outside of your home that drips water, there's a good chance that this is actually just your AC condensate drain, which is supposed to carry water outside your home. Still, this isn't always the case, and some pipe leaks do need to be investigated.

Why is there a drain outside my house?

If it's in your yard, that's your main sewer line. Typically the only reason it would be opened and cleaned out is if you're having issues in your own house with multiple backed up drains caused by a blockage between your house's pipes and the main line. That is really strange the cap was off...

Should my exterior AC drain pipe be dripping water?

If it's the drain that comes directly from the unit, then yes, it should be dripping. If it's the drain to the emergency overflow, then no, it should not be dripping.

Why is there a drain pipe in my yard?

One of the main reasons why there are drains in your backyard is because of storm water management. Driveways and rooftops are impervious surfaces that prevent water from penetrating into the soil during heavy rainfall.

How Your Home Plumbing Works (From Start to Finish) | GOT2LEARN

What is the pipe coming out of my yard?

The Pipe in your yard is called a cleanout. A clean out can be 6 inch clay, 6 inch PVC, 4 inch clay or 4 inch PVC. The cleanout is used to troubleshoot potential problems within the collection system.

What is the drain in my front yard called?

Catch Basins. A catch basin drainage system, also known simply as a “yard drain,” is a key component of many modern stormwater management systems. These basins are designed to collect and manage rainwater runoff efficiently.

Why is the drain on the side of my house dripping water?

Water dripping and a big ol' rust stain on the side of the house are signs that you have a drain line issue. Typically, we see this whenever the system is in the attic. It probably means that your primary drain line is clogged and is overflowing into your secondary drain pan.

What does outside AC drain line look like?

You'll find a white PVC or copper pipe located near your outdoor unit—this is where the drain line ends. Near your indoor unit, you'll find a vertical PVC pipe with a cap on it, which acts as the access point for the condensate drain.

Is it bad if your AC is leaking water outside?

Under normal operation, your air conditioner should only leak or produce condensation while operating. Then, the small puddle of water should dry up on a hot day. A telltale sign you could be in need of air conditioner repair is if the water leak persists for a day or more.

Should there always be water in outside drain?

When looking in the drain, there should be flowing water and no visible signs of blockage. A blockage can be identified if the water in the drain is blocked and not flowing. Outside drains are often blocked up with leaves and other types of debris and dirt.

How to unclog an outside drain pipe?

The simplest option is to use a drain snake or auger to pierce and break up the clog. If you need something stronger, you can try using high-pressure water from a power washer to force clogs through the pipes. If you use a power washer, be sure to wear gloves as well as eye and ear protection.

What is the white pipe coming out of the ground?

A white plastic pipe is the inspection port for the sewer pipe between your house and the main sewage system. It must not be buried or covered by vegetation because it can be used for service and maintenance.

What is the overflow pipe outside the house?

What is an overflow pipe? An overflow pipe leads from a water storage tank or cistern inside your home to the outside. If the water in the tank or cistern fills up to a higher level than it should, the excess water flows down through the overflow pipe and runs outside, rather than leaking into your home.

Why is water dripping from my roof outside?

Sometimes, homeowners can be surprised when they hear their clogged gutters have caused their roof to leak. Gutters are meant to siphon water off your roof and away from your property, via a downspout. When a gutter becomes stuffed with leaves, twigs and other debris, the water has nowhere else to go.

Why do I hear water running outside my house?

A bad seal could cause running water. Water heater – make sure to check that your water heater isn't leaking into your homes foundation. Homes exterior – double-check the exterior of your yard to make sure your sprinkler system isn't leaking and causing a drip sound.

Why is water dripping from my AC drain pipe outside?

One reason outside air conditioners leak water is due to a damaged or blocked drain line. Condensation is a product of your AC unit's cooling process. The evaporator coils drip the water into a collection drain pan, from where it flows out of your home through a condensation line.

What does an outside condensate pipe look like?

The condensate pipe is usually a white PVC-U pipe, similar to one you may find on a washing machine or sink waste pipe which usually goes outside into a drain.

How to tell if a condensate line is clogged?

Signs of An AC Drain Line Clogged
  1. Musty, moldy smell near your indoor unit or in air from the registers/vents.
  2. Standing water near the indoor unit.
  3. Water damage in areas near the indoor unit.
  4. AC system is not cooling your home.
  5. AC system shuts down or doesn't turn on.

What is the pipe dripping water outside a house?

The pipe dripping water outside your house is an overflow pipe that's most likely connected to an overflowing toilet cistern, cold water or central heating feed and expansion tank.

How to unclog a condensate drain?

How to Unclog Your AC Drain Lines in 9 Steps
  1. Turn Off Your Air Conditioner. ...
  2. Locate the Drain Line Pipe. ...
  3. Remove the Cap From the Pipe. ...
  4. Inspect the Drain Line Pipe. ...
  5. Unclog the Drain Line Pipe. ...
  6. Pour in Vinegar. ...
  7. Use a Wet/Dry Vacuum Cleaner. ...
  8. Reconnect the Cap to the Drain Line Pipe.

What is the drain on the side of my house called?

The two most common drain pipes that most people have on the side of their house are: Air conditioner condensate lines (AC drain line). Water heater pressure relief valve lines (PRV drain line).

What is the drain outside my house?

This access is sometimes referred to as a cleanout, clean-out, drain clean out, sewer clean out, or clean out pipe. All those terms mean the same thing. If installed correctly, your sewer line should have a cleanout, ideally located in your yard, between the home and the street or septic tank.

What does a swale drain look like?

Like a trench drain, a swale is a surface water drainage device. However, it's a lot more subtle in terms of its appearance in the landscape. A swale is like a ditch, but it's broad and shallow, and usually covered or lined with turfgrass or other vegetation.

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