Dometic MasterFlush 8740 12V Electric Macerating Toilet White

The Dometic MasterFlush 8740 (part 304874020) is the premium 12-volt electric macerating marine toilet in the Dometic MasterFlush 8700 series. The marine head built to feel like a residential toilet: full-size ceramic bowl with the elongated seat shape and the Slow-Close seat hinge that you'd find in a home bathroom, mounted on a marine macerator pump base that handles waste discharge to the boat's holding tank or directly overboard (where local discharge laws allow). The right marine head for a master cabin or guest head install where the owner wants the head to feel like a house bathroom rather than a basic boat compromise.

What macerating means and why it matters on a boat. A marine macerating toilet has a built-in chopping pump that grinds waste and toilet paper into a slurry as part of the flush, then pumps the slurry through small-diameter (1 inch typical) discharge plumbing to the holding tank or overboard discharge fitting. Compared to gravity-feed marine toilets (which need large-diameter 1.5-inch or 2-inch discharge plumbing and a downhill run from the toilet to the tank), macerating toilets can route the discharge through small-diameter plumbing, around obstacles, and up against gravity if needed. That makes the macerating toilet the only practical choice for many boat layouts where the toilet sits below or far from the holding tank.

30% more efficient macerator. Dometic's MasterFlush 8700 series macerator runs at 30% higher efficiency than older marine macerator heads. The result: the flush is quieter (you don't hear the loud grinding of older units), shorter (the cycle finishes faster), and uses less battery current per flush. For boats running off battery alone (no shore power, no engine running), the lower current draw matters: each flush takes less out of the battery so you can flush more times before needing to recharge.

Residential-size elongated bowl with Slow-Close seat. The bowl is the same size as a residential household toilet bowl with the elongated (front-to-back longer) seat shape. The Slow-Close seat hinge prevents the seat lid from slamming down hard - the lid drops to the seated position smoothly under spring control instead of dropping with gravity. Both features are quality-of-life upgrades over budget marine toilets that use undersized round bowls and basic friction-hinge seats. For boat owners who entertain guests onboard, the residential-feel head is one of those details that makes the boat feel less like a boat and more like a vacation home.

Dual-flush mode: Normal or Low. The electronic flush handle gives you two flush options selectable on the handle: Normal flush (full water volume for solid waste, typical residential flush feel) and Low flush (reduced water volume for liquid waste only, conserves fresh water on boats running off the boat's water tank for rinse water, conserves holding tank capacity). For long-passage cruising boats and houseboats where water and holding tank capacity matter, the dual-flush capability is significant.

Raw water OR fresh water rinse. The 8740 model is plumbed to use either raw water (sea water pumped in from a thru-hull) for rinse water or fresh water (from the boat's pressurized fresh water system) for rinse water. Most owners run raw water rinse to conserve fresh water capacity for drinking and washing. The fresh water rinse option is for boats whose layout makes raw-water plumbing impractical, or for owners who don't want any sea-water smell in the head over time.

Through-the-floor or through-the-wall discharge fittings. The discharge plumbing exit can be configured at install to exit through the floor (down through the deck below the toilet base) or through the wall (out the back of the toilet base into the wall behind). The flexibility lets the toilet fit a wide range of boat plumbing layouts where the holding tank is in different positions relative to the head.

Electronic flush handle with chrome finish. The flush handle is electronic (a small touch / press control rather than a mechanical lever) with a chrome finish that matches typical marine bathroom fittings. The electronic handle is the user interface to the dual-flush mode (different press patterns for Normal vs. Low flush). For owners who want a more discreet flush control, an optional flush touch pad is available as an aftermarket Dometic accessory that mounts in a wall location separate from the toilet itself.

9.8-foot suction lift. The macerator pump can pull rinse water from a raw-water source up to 9.8 feet below the toilet (suction lift). For most boat installations the rinse water source is significantly closer than 9.8 feet, so the lift capacity is well within the typical operating range. For boats where the toilet sits high above the waterline (flybridge head, raised second-deck head), the suction lift capacity is what makes the install work.

Specs and dimensions. 21.5 inches deep by 19 inches tall by 14.75 inches wide. Weight: 41.5 lb (the toilet itself). Standard household toilet height for comfortable seating. Ceramic bowl construction (not the cheaper plastic that some marine toilets use). 12V DC operation, the marine standard. Operates from the boat's 12V battery system with appropriate fuse protection.

Installation. The 8740 mounts to the floor of the head compartment via standard floor-mounted bolts (similar to a residential toilet install). Plumb the discharge to the holding tank or overboard discharge per local discharge regulations. Plumb the rinse water inlet to either a raw-water source (sea water thru-hull with strainer) or the boat's fresh water system. Wire the 12V DC power feed with appropriate fuse (typically 20-30 amps depending on cable run length). Total install time is typically 4-6 hours for a fresh install, less for a like-for-like replacement of an existing marine toilet.

What's in the box. The MasterFlush 8740 toilet (ceramic bowl, electric macerator pump base, elongated Slow-Close seat, electronic flush handle), the standard discharge fitting kit, the rinse water inlet fittings, the install instructions, and the operations manual. Required separately: discharge hose to the holding tank, raw-water inlet hose and seacock, holding tank vent, and the 12V wiring with appropriate fuse.

California Prop 65 warning applies (the ceramic glaze contains arsenic, a Prop 65-listed substance). The warning is the standard label for ceramic toilet products in California and isn't unique to the Dometic 8740.

Dometic warranty applies. Same-day shipping before 3 PM ET on in-stock units.