Best torpedo level

Klein's 935RBP is the level I'd hand someone who runs drain pipe. Klein says it reads plumb, level, 45 degrees and pitch in precise 1/8-inch increments. That pitch vial is the whole reason it's my top pick.

Drain slope is written in inches per foot. Georgia's plumbing code table asks for at least 1/4 inch per foot on drain pipe 2-1/2 inches and smaller, and 1/8 inch per foot on 3 to 6 inch pipe. A plain level only tells you the pipe isn't flat. A pitch vial tells you whether it's falling enough.

Klein lists the accuracy at plus or minus 0.029 degrees. That works out to about 0.006 inch per foot, which is small next to the 1/8 or 1/4 inch per foot you're setting. The chart further down shows it over a 10 foot run.

The body is billet aluminum, anodized orange, 8 inches long, 1.5 inches wide and 0.75 inch tall. Klein lists the weight at 0.42 pound and rates it for a drop of 6.6 feet. The tapered nose slides into a pocket.

It has four rare-earth magnets. Klein's patented magnet track holds them in, so a magnet doesn't pop out after a few drops. The V-groove on the bottom sits on round pipe, and the large top-view window lets you read the vials from above when the pipe is over your head.

One limit to know: magnets only grab steel and iron. On copper or PVC drain pipe, the V-groove is what keeps the level on the pipe, not the magnets. That's true of every level on this page.

It doesn't have a 30 degree vial. For plumbing, I'd trade that for the pitch vial every time. It was sold by Amazon.com and in stock on the day of the update.

Johnson's 1435-1200 is the long one here, at 12 inches. It has the same job as the Klein: four vials for plumb, level, 45 degrees and slope. Johnson says its Multi-Pitch vial reads slope in 1/8-inch increments.

I'd pick it for long drain runs. A longer body sits across more of the pipe, so one low spot or a bit of sag right under the level throws the reading off less. It still isn't a 2 or 4 foot level, but it's 50 percent longer than the Klein.

Johnson lists the accuracy as .75 millimeter per meter. That's about 0.009 inch per foot. It's looser than Klein's figure, and still small next to the 1/8 inch per foot you're setting on 3 or 4 inch pipe. Johnson backs it with a lifetime accuracy warranty.

The vials are oversized, 1/2 inch across. Johnson calls them SurroundView, and says they reflect ambient light so you can read them in dim spots. There's also a top-read window, so you can look down at the vial when the pipe is at chest height.

The frame is solid aluminum, which Johnson calls Job Site Tough, with a V-groove that fits pipe and conduit. Johnson's GripTight rare-earth magnets sit in the V-groove and hold to flat or round ferrous metal, which means steel or iron.

On 3 or 4 inch drain at 1/8 inch per foot, a 10 foot run drops 1-1/4 inches, and the Johnson reads that slope right off the vial. On 1-1/2 or 2 inch pipe it's 1/4 inch per foot, the other mark you'll use most.

Two things it doesn't list: a weight and a drop rating. The orange body is easy to find in a bucket. It was sold by Amazon.com and in stock on the day of the update.

The 935RBLT is Klein's lighted torpedo level. Its vials are lit by LEDs, which Klein says makes them easy to read in any lighting. If you've tried to read a bubble in a crawlspace with a flashlight in your teeth, you know why that matters.

Klein lists three vials: level, 90 degrees and 45 degrees. There's no pitch vial, so on drain pipe you'd read level and use the fall table above. That's the trade, and it's why this is my pick for the dark, not my top pick.

Klein lists the same accuracy as the 935RBP, plus or minus 0.029 degrees. The body is 9 inches long, 1.8 inches wide and 0.75 inch tall, and weighs 11.2 ounces. It's billet aluminum in high-visibility orange, with the same patented magnet track that keeps the rare-earth magnets in.

It runs on two AAA batteries, which come in the box. Klein says it shuts itself off after 3 minutes to save the batteries, so a light left on in a tool bag won't drain them overnight.

Pair it with the fall table. At 1/4 inch per foot, a 6 foot trap arm on 1-1/2 inch pipe drops 1-1/2 inches. You measure that drop down from a level line, and the lit vials make that level line easy to set in the dark.

Klein calls it water and impact resistant. It doesn't list an IP rating or a drop height for this model, so I wouldn't leave it sitting in standing water under a house.

The V-groove fits pipe and conduit, the top-view windows read from above, and the tapered nose slides into a pocket. The CPSC recall search turned up nothing for this model; Klein's recalls were for power stations, voltage testers and clamp meters. It was sold by Amazon.com and in stock on the day of the update.

Swanson's Savage TL043M is the one I'd pick for steel. It has four rare-earth neodymium magnets, and Swanson says they hold it to ferrous pipe and stock. On black pipe, cast iron or a run of strut, that means you can set the level, let go and use both hands on the pipe.

The body is solid billet aluminum, anodized, and 9 inches end to end. Swanson says it's three times stronger than extruded torpedo bodies. It's also the heaviest level here that lists a weight, at 0.72 pound.

Swanson publishes its accuracy plainly: .029 degree, or .0005 inch per inch. That's the same figure Klein lists, and it's the number I used in the accuracy chart above.

It has four vials, at 0, 30, 45 and 90 degrees. Swanson says its top-read windows show the 0, 45 and 30 degree vials from the top of the body, so you don't flip the level to read it. Swanson's milled vial ports catch and reflect light at the bubble, which helps in dim spots without batteries.

On a cast iron stack, the 90 degree vial and the magnets together let you check plumb with no hands on the level. Cast iron holds a magnet. The PVC or copper tying into it won't, so steady the level there.

Swanson also engraves SAE and metric rules into the body. On a torpedo level that's a small thing, but it's handy for marking a short cut or checking a stub-out height.

Swanson's guarantee covers the original buyer for life and says the level keeps its stated accuracy. The guarantee is void if the level is bent, twisted or otherwise damaged.

There's no pitch vial. For drain slope, read level and use the fall table, or pair it with the Klein 935RBP. It was sold by Amazon.com and in stock on the day of the update.

IDEAL makes this level for electricians, but its vial set has something the plumbing levels don't: a 22.5 degree vial. IDEAL's listing gives it five vials, at 0, 22.5, 30, 45 and 90 degrees, plus a bull's-eye vial for lining up both directions at once.

That 22.5 degree vial matches a 1/16 bend, the drain fitting that turns 22.5 degrees. If you're setting a 1/16 bend and want the pipe after it at the right angle, this is the one level here with a vial for it. It also has the 45 and 90 degree vials for 1/8 and 1/4 bends, so one level covers all three common drain fittings.

The bull's-eye vial reads level in every direction. I'd use it on a flat surface, like the top of a water heater or a washing machine, where you want level both ways without turning the tool. It helps on a toilet flange too, where the flange should sit flat both ways before the bowl goes on.

IDEAL says the body is CNC machined from 6061 aluminum billet. It has a V-groove on the bottom for pipe or conduit, and oversized neodymium rare-earth magnets. IDEAL also lists a built-in thumb winder and a contoured screw for grip, and says it can attach to other levels when you need it longer.

Two extra vials come in the box. IDEAL uses corrosion-resistant brass screws to hold the vials, so you can swap a cracked vial instead of buying a new level.

What it doesn't have is a pitch vial, and IDEAL doesn't list an accuracy figure or a weight. For drain slope, I'd still reach for the Klein 935RBP. This one earns a spot for the angles and the bull's-eye. It was sold by Amazon.com and in stock on the day of the update.

IDEAL's 35-207 is the smallest level here, at 6 inches. IDEAL says it's handy in tight spaces, and that's how I'd use it: inside a sink base, between studs, or on a short trap arm where a longer level hangs off both ends.

IDEAL's listing gives it four vials, for 0, 30, 45 and 90 degrees. It has no pitch vial, so read level and use the fall table. On a trap arm of a few feet, that's quick math: 1/4 inch per foot over 3 feet is 3/4 inch.

Six inches is half the Johnson's length, so it sits flat on a short piece of pipe that a 12 inch level would bridge. It also fits on a stub-out, where you check that a supply or drain stub comes through the wall square before the fixture goes on.

IDEAL calls its magnets oversized neodymium rare-earth magnets, and the listing names a magnetic jaw for hands-free use. The bottom has a V-groove for stable mounting on pipe or conduit.

The body is made from 6061 T6 aluminum, per IDEAL's product page, and has IDEAL's Thumb Winder conduit wheel with a contoured screw. That's an electrician's feature for bending conduit. It doesn't get in the way on pipe.

A pair of replacement acrylic vials comes in the box, held by corrosion-resistant brass screws instead of plastic or glued caps. IDEAL posts vial replacement instructions on its site and covers the level with a limited lifetime warranty.

Its spare vials and brass screws are why I'd trust it to last. For plumbing I'd carry it as a second level next to the Klein 935RBP, for the spots the 8 inch body won't reach. It was sold by Amazon.com and in stock on the day of the update.