Often, the pipes you see outside your house are essential drain lines for key household systems.
While various pipes could be present outside a property for different purposes (like gas lines, water supply, or sewer cleanouts), the provided reference highlights two types of drain pipes that are very common to find on the side of a house.
Common Drain Pipes Outside Your House
According to common household setups, including information from the reference provided, the two most frequently seen drain pipes on the exterior of many homes are:
Air Conditioner Condensate Lines (AC Drain Line)
- Purpose: Your air conditioning system cools air by removing heat and moisture. This process creates condensation, similar to how a cold drink "sweats." The AC drain line's job is to safely channel this excess water away from the unit and your home's foundation.
- Appearance: Typically, this is a small diameter pipe, often made of PVC (a type of plastic), usually white or sometimes grey. It often emerges from the wall near your outdoor AC unit or sometimes near the indoor air handler location. You might see water slowly dripping from it on humid days when your AC is running.
Water Heater Pressure Relief Valve Lines (PRV Drain Line)
- Purpose: Water heaters operate under pressure. If the pressure inside the tank gets too high, a crucial safety device called the Pressure Relief Valve (PRV) opens to release hot water and steam, preventing a potentially dangerous situation. The PRV drain line directs this released hot water safely outside the house.
- Appearance: This pipe is connected to the pressure relief valve on your water heater (usually near the top). It can be made of metal (like copper) or approved plastic (like CPVC) and runs downwards and then often through the wall to the exterior. You should generally not see water coming from this pipe unless the PRV valve is actively releasing pressure, which could indicate a problem with the water heater or the valve itself.
Here's a quick summary of these common external drain pipes:
| Pipe Type | Common Location | Purpose | What Comes Out? |
|---|---|---|---|
| Air Conditioner Condensate Line | Near AC unit or air handler | Drains moisture condensed by AC | Water (often dripping) |
| Water Heater Pressure Relief Valve Line | Near water heater/exterior wall | Safely releases excess water/steam pressure | Hot water/steam (infrequent) |
Why Are These Pipes Necessary?
These drain lines are essential for the proper and safe operation of your home's mechanical systems.
- The AC drain line prevents water damage around your AC unit and inside your home, maintaining system efficiency.
- The PRV drain line is a critical safety feature that protects your water heater from over-pressurization, preventing potential leaks or ruptures.
While these two are frequently encountered, other pipes might be present outside your home depending on its specific systems and age, such as sewer cleanout ports, irrigation system pipes, or even vents. However, the small-diameter drain pipes often visible near the ground are very commonly either your AC or water heater relief lines.
