Where Are These Sewer Lines Going?! | The Outhouse

In this post, we’ll walk through the process of investigating unknown plumbing lines in an older building. We’ll explore each step, from the initial curiosity about the toilet’s drain path, to pulling the toilet and sending a camera down the line to see what’s going on. Along the way, you’ll learn about the tools, techniques, and best practices that professional plumbers rely on to trace drains, locate potential blockages, and assess the overall viability of a plumbing system.

Why Locating Sewer Lines Matters

Knowing where your sewer lines run is crucial for many reasons:

• Preventing Damage: If you start renovating or digging on your property without knowing where the lines lie, you risk damaging the pipes—or injuring yourself.
• Planning Renovations: Converting a barn into a more functional space (like an office, guest suite, or workshop) often involves extending or upgrading the plumbing system. You need accurate information on existing lines for proper design.
• Ensuring Proper Drainage: You can’t fix or upgrade what you can’t see. By locating lines, you can diagnose any drainage issues, clogs, or leaks before they turn into bigger, costlier problems.
• Code Compliance: When remodeling or installing new fixtures, local building codes may require that you know how your system is routed and connected—especially if you need a permit.

In this scenario, the outhouse structure in the barn has a mysterious toilet and some indication of a water supply. Before investing in a new bathroom setup, you have to figure out where everything drains (or if it drains at all).

Step 1: Basic Inspection of the Space

The first step is to perform a visual inspection:

1. Check the Roof Vents: Before sewer cameras were available, plumbers often deduced the path of pipes by looking for vents on the roof. Vents give a clue about where vertical stacks run.
2. Examine the Existing Toilet: In this case, the toilet was hidden under years of accumulated junk. After clearing out the space, you can see it’s plumbed with older parts—three-eighths-inch copper tubing for the supply line, a lead or PVC bend in the floor, and a standard flange, although not installed to modern best practices.
3. Look for Valves and Visible Lines: In many barns or outbuildings, you might see makeshift water lines or a partial system that was never fully completed. Note any shut-off valves or stubs that may be accessible.

Even this quick survey raises questions: Has the toilet ever actually worked? Is there a functional water line to it? If so, where’s the shut-off? And most importantly, where do the waste lines lead?

Step 2: Disconnecting the Water Supply

Before you remove the toilet, you want to see if the water is still live. Here’s how this step might unfold:

1. Shut Off Any Known Valves: If you know where the barn’s main water valve is (or the property’s main shut-off), turn it off. In older structures, you might have to guess or do a trial-and-error approach.
2. Disconnect the Flexible Tubing: In the example above, the water connection used a piece of 3/8-inch copper tubing—something you don’t see as often today. Modern plumbing typically uses flexible, braided supply hoses.
3. Test for Flow: Once the tubing is disconnected, you can carefully open the valve (or carefully uncap the line) to see if water comes out. Always be prepared to shut it back off quickly if you have active flow and no easy way to manage the water.

In our scenario, the plumber isn’t sure if the water line is live. It’s not visibly dripping, so it might be off. But because the shut-off valve looks old and untested, there’s a risk that turning it could cause leaks or break the valve altogether. Proceed with caution in these circumstances.

Step 3: Removing the Old Toilet

With the supply line disconnected, it’s time to pull the toilet:

1. Pop Off Bolt Caps: Toilets are usually secured with two bolts on either side, each capped. These caps can be brittle with age.
2. Unscrew or Remove Rusted Bolts: Older installations might have corroded bolts that need penetrating oil or careful work with pliers. In the example, they come off surprisingly easily—an unusual but welcome surprise.
3. Lift the Toilet Straight Up: Once the bolts are free, gently rock the toilet side-to-side to break the wax ring seal, then lift it off. Place the toilet on a suitable surface (or cardboard) to avoid making a mess.
4. Inspect the Flange and Wax Ring: Old wax rings might be partly disintegrated or incorrectly installed. You might also find the flange is set into the concrete floor instead of on top, which is not ideal by current code standards.

Our outhouse scenario reveals that the toilet drain is either a lead bend or a piece of older PVC. The wax ring was partially effective, but definitely not optimal. This is a clue that the plumbing might be older, improvised, or incomplete.

Step 4: Running a Sewer Camera Inspection

A sewer camera is one of the best ways to see where a hidden drain goes. This device is exactly what it sounds like: a small camera on a flexible cable that can be fed through the drain line to provide a video feed of its interior.

1. Prepare the Camera: Turn on the camera’s monitoring system. Modern systems often pair with a tablet or have built-in screens.
2. Insert the Camera into the Drain: Slowly feed the cable into the toilet drain opening. In our case, the plumber sees that after a short run, the camera hits some dirt or debris.
3. Rinse Away Debris (If Possible): If there is a hose connection available, gently spray water into the line to clear any dirt. This step can be tricky if the water supply is off or you’re unsure of water pressure. Be careful not to flood the area if you don’t know where the water will go.
4. Note Pipe Transitions: You may see changes in pipe material, diameter, or connections to other lines. The image might transition from lead or ABS to PVC or even Orangeburg pipe if it’s an older installation.
5. Observe Standing Water: The camera might reveal sections where water doesn’t drain, indicating a sagging pipe or partial blockage. If the camera dips underwater, it can be hard to see beyond that point without further clearing.

In the video example, the plumber discovers that around 10–16 feet into the line, there’s standing water and some debris. The pipe material also seems to switch. There’s no immediate sign of a big open path to a known septic tank. It might drain into an older system or the ground. More investigation is needed.

Step 5: Using a Locator to Trace the Drain’s Path

Modern sewer cameras often have built-in transmitters, and you can use a separate locator device above ground to follow the camera head’s signal. This technique helps pinpoint the drain’s route under floors or soil:

1. Activate the Locator: Turn on the receiver, which picks up signals from the camera’s transmitter.
2. Walk Above Ground: Follow the beeps or signals to find the camera’s position. The locator often has a visual gauge that shows you depth and direction.
3. Mark the Path: When you find the strongest signal, mark the ground with spray paint or a small stake. This step helps outline the pipe’s direction and depth.
4. Adjust Camera Depth: Sometimes, you’ll feed the camera further, then pause to do additional locates at each junction or suspected turn.

In this scenario, the plumber finds that the drain is only about a foot deep in some places—suggesting shallow pipe placement. The line likely runs under a concrete slab or out into the yard. The presence of water in the camera’s feed indicates that the line is either blocked downstream or sits in an area that doesn’t drain well.

Common Pipe Materials in Older Buildings

While investigating a decades-old outhouse drain, you might encounter a variety of materials:

• Lead Bends: Common in older bathrooms, these are soft metal tubes that connect toilets. They’re rarely used in new construction now.
• Cast Iron: Popular in homes built before the 1970s. Cast iron is durable but prone to corrosion over time.
• Clay or Orangeburg: In certain regions, older sewer lines were made from clay segments or compressed tar paper (Orangeburg). Both can deteriorate and collapse after many decades.
• PVC/ABS: More modern materials. PVC (white) and ABS (black) are standard in residential construction today. They’re lightweight, relatively easy to install, and resistant to corrosion.

Identifying these materials helps you predict potential problems, from root intrusion to structural collapse.

Possible Next Steps for the Outhouse

Depending on the ultimate goal for the barn/outhouse area, the homeowner or plumber might:

1. Find or Install a Septic Tank: If the line doesn’t connect to a working tank, you may need a new system or a tie-in to an existing one—if codes allow.
2. Replace or Repair the Drain Pipe: If the existing pipe is sagging or collapsed, a partial or complete replacement might be necessary.
3. Update the Flange and Wax Ring: If reusing the toilet, install a proper 4-inch flange above the finished floor level for a reliable seal.
4. Add a Functional Water Supply: If the old valve or line is unreliable, consider installing a modern shut-off valve and flexible supply line to ensure consistent, leak-free service.
5. Revamp the Space: If the outhouse is to become an actual functional bathroom or a comfortable office with running water, plan an appropriate layout, including vents, drains, fixtures, and code-compliant venting.

Pro Tips for Investigating Unknown Plumbing

• Start Simple: A quick visual inspection can reveal a lot. Look for root vents, old piping stubs, or changes in floor slope.
• Use the Right Tools: A sewer camera and locator are invaluable for mapping unknown drains. Without them, you’re guessing at best and tearing up floors at worst.
• Proceed Gently: Old valves and fittings can break if forced. If you must test water flow, be ready to turn it off quickly or patch a leak on short notice.
• Document Everything: As you discover the drain path, record the depth and direction at key points. You might need this info for future repairs, permits, or expansions.
• Consider Professional Help: If you lack experience or the right equipment, it may be more cost-effective to hire a professional plumber who can trace the lines accurately and give you a reliable assessment.

Challenges You Might Encounter

• Blocked Lines: Standing water or dirt in the pipe can obscure the camera’s view. You may need to jet or snake the line first.
• Collapsed or Missing Segments: In very old or neglected properties, sections of pipe might be missing altogether, requiring a brand-new installation.
• Outdated or Non-Compliant Systems: The original drain might have never been installed to code (or codes have since changed). Upgrading it could be mandatory.
• Confusion Over Property Layout: Outbuildings sometimes have unofficial tie-ins that the previous owners never documented.

Assessing Viability and Making a Decision

After you’ve investigated and possibly located the sewer line, the next step is to decide how to proceed. Consider:

1. Repair vs. Replacement: If a short section is damaged but the rest is intact, a simple repair may suffice. If multiple sections are compromised, a full replacement might be cheaper in the long run.
2. Meeting Future Needs: If you envision a fully functioning bathroom in the barn, you might want to upgrade to modern materials and install a new vent system.
3. Budget and Timeline: Larger projects involving septic systems, new plumbing lines, or excavation can be costly. Map out your budget and timeframe before tearing into the ground or slab.
4. Permits and Inspections: Check local regulations. In some places, you’ll need a permit for any substantial plumbing work or to connect to a municipal line.

Conclusion

Tracing mystery sewer lines in an old barn or outhouse can be like peeling back layers of history—complete with hidden pipes, improvised solutions, and sometimes even a missing septic tank. By using a combination of hands-on inspection, modern tools like sewer cameras and locators, and a methodical approach to uncovering the path, you can figure out exactly what you’re dealing with and decide on the best course of action.

Whether the goal is to convert the space into a functional bathroom, remove a defunct fixture, or ensure you’re compliant with local regulations, gathering the right information is essential. With patience, caution, and the correct equipment, you can transform an unknown plumbing tangle into a clearly mapped system—ready for whatever renovations or upgrades come next.