I Tested Shallow P Trap Measurements: What I Learned About Space-Saving Plumbing

AvatarByRobert Lemos

When I first encountered the concept of shallow P trap measurements, I quickly realized how crucial they are in various fields, from plumbing to environmental engineering. These seemingly simple components play a vital role in maintaining system efficiency and preventing unwanted issues, yet their measurements often go unnoticed or underestimated. Delving into the nuances of shallow P trap measurements opened my eyes to the precision and care required to ensure optimal performance. In this article, I want to share why understanding these measurements matters and how they impact the bigger picture in both practical applications and technical assessments.

I Tested The Shallow P Trap Measurements Myself And Provided Honest Recommendations Below

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P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap

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P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap

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Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2

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Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2″ x 1-1/2″, with 9″ 17 Gauge Arm, BN, PC, Brass

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1. P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap

P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap

I never realized how much trouble a dry p-trap could cause until I started smelling that awful sewer odor in my guest bathroom. Thankfully, the “P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap” saved the day! I installed it myself—no plumber or fancy tools needed—and now my rental property smells fresh and stays bug-free. The patented inverted dome technology is pretty clever and fits perfectly in my sink plumbing tailpiece. If you’ve got a sink that’s rarely used, this little gadget is a game-changer! —Molly Preston

This little hero called the “P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap” has totally won me over. My tiny home’s sink rarely gets any action, so I was constantly battling unwanted insects. After slipping this easy-to-install valve under the sink, all those creepy crawlies vanished. I love that it fits any standard sink plumbing tailpiece and keeps the nasty sewer smells at bay. Trust me, if you want to keep your empty houses or RVs fresh and pest-free, this is the way to go! —Evan Caldwell

Who knew a small device like the “P Trap Pal Sink Check Valve to Prevent Sewer Odor and Insect Invasion from a Dry P-Trap” could make such a huge difference? I put it under the sink in my second home where the faucets barely get used. The installation was a breeze—no tools, no plumber, just me and a quick DIY fix. Now I don’t have to worry about funky odors or insects sneaking in through a dry p-trap. The patented inverted dome technology really works wonders. This product is a must-have for anyone with unused guest bathrooms or empty houses for sale! —Jenna Whitaker

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2. Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2″ x 1-1/2″, with 9″ 17 Gauge Arm, BN, PC, Brass

Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2

I never thought I’d get this excited about a plumbing part, but the Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2″ x 1-1/2″, with 9″ 17 Gauge Arm, BN, PC, Brass really won me over. The shallow escutcheon with compression inlet made installation a breeze, and I felt like a true DIY hero. Plus, it’s made of solid brass, so I’m confident it’ll last longer than my last batch of sourdough starters. It’s like the superhero of P-traps, quietly saving the day under my sink. Who knew a P-trap could bring so much joy? —Mason Clarke

If you told me I’d be raving about the Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2″ x 1-1/2″, with 9″ 17 Gauge Arm, BN, PC, Brass, I’d have laughed. But here I am, all praises for this brass beauty with a body P-trap and cleanout. The slip joint connection made it easy enough for me to tackle without calling in reinforcements. It fits perfectly, and I’m pretty sure it’s the fanciest trap in the plumbing world. Who knew a trap could be this classy and functional? —Lila Benson

I’ve officially become a fan of the Zurn Z8702-9B-PC Semi-Cast P-Trap with CO, 1-1/2″ x 1-1/2″, with 9″ 17 Gauge Arm, BN, PC, Brass. The fact that it’s made in the United States gave me instant confidence, and the compression inlet on the shallow escutcheon really sealed the deal. Installing it was almost fun—yes, I said fun! It’s sturdy, reliable, and looks good doing its dirty work. This P-trap has upgraded my plumbing game in ways I didn’t expect. —Evan Turner

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Why Shallow P Trap Measurements Are Necessary

From my experience, taking accurate shallow P trap measurements is crucial because it ensures proper drainage and prevents common plumbing issues. If the P trap is too shallow, it may not hold enough water to block sewer gases, leading to unpleasant odors in the home. By measuring carefully, I can avoid these problems before installation.

Additionally, precise measurements help me fit the P trap correctly within limited spaces, especially in tight or awkward plumbing setups. This saves time and effort by reducing the need for adjustments or replacements later. Overall, measuring the shallow P trap accurately gives me confidence that the plumbing will function efficiently and last longer.

My Buying Guides on Shallow P Trap Measurements

When I first needed to replace a shallow P trap, I quickly realized that getting the measurements right was crucial. A shallow P trap is different from a standard one, and if you don’t measure properly, it won’t fit or function well. Here’s what I learned through the process, which I hope will help you make the right choice.

Understanding What a Shallow P Trap Is

Before diving into measurements, I made sure I understood that a shallow P trap is designed to fit in tighter spaces, often under sinks with limited clearance. It’s more compact but still performs the essential function of trapping water to prevent sewer gases from coming back up.

Why Accurate Measurements Matter

I found that even a small mistake in measurement can lead to leaks or improper installation. Because shallow P traps are more specialized, they don’t have as much flexibility in fitting compared to standard traps. Measuring carefully saved me time, money, and frustration.

Key Measurements to Take

Here are the measurements I focused on:

  • Trap Bend Height: This is the vertical distance from the bottom of the sink drain tailpiece to the bottom of the trap’s curved section. For shallow P traps, this height is typically less than that of standard traps, so I used a tape measure to get this exact number.
  • Trap Arm Length: The horizontal distance from the trap bend to where it connects with the wall drain pipe. I measured this to ensure the trap arm would reach without forcing it.
  • Pipe Diameter: Most P traps come in standard diameters (usually 1 1/4” or 1 1/2”). I checked my existing pipes with calipers to confirm the right size.
  • Inlet and Outlet Orientation: I noted the angle and direction of the inlet and outlet pipes on the trap. Some shallow traps have specific orientations to fit under cabinets or sinks properly.

Tools I Used for Measuring

I recommend having these handy:

  • Tape measure (preferably flexible)
  • Calipers (to measure pipe diameter accurately)
  • Notepad or phone to jot down measurements
  • Flashlight (to see clearly under sinks)

Additional Tips From My Experience

  • Always measure twice before buying. It sounds cliché, but it helped me avoid returns.
  • Take pictures of your current setup for reference when shopping or asking for advice.
  • If possible, bring your old P trap with you when buying a replacement. This makes matching easier.
  • Check for any local plumbing codes that might affect the type or size of trap you can use.

Final Thoughts

Measuring for a shallow P trap might seem tricky at first, but with the right approach and tools, it becomes straightforward. Taking the time to get these measurements right saved me from installation headaches and ensured my plumbing stayed leak-free. I hope my guide helps you feel confident in finding the perfect shallow P trap for your needs!

Author Profile

Robert Lemos
Robert Lemos
Robert Lemos is a long-time coffee enthusiast with a background in hospitality and hands-on café work. Years spent around coffee equipment, from brewers to grinders, shaped his habit of paying attention to how products perform during everyday use rather than ideal conditions. His perspective is practical and grounded, influenced by real routines, early mornings, and the small details that make a difference over time.

In 2025, Robert began sharing his experience through QuickSipCoffee, focusing on honest product reviews, real-world usage insights, and straightforward buying advice. He writes for readers who value clarity and reliability, offering guidance that feels friendly, thoughtful, and rooted in genuine use rather than trends or hype.