The Dometic SeaLand T Series Waste Discharge Pump – 12V (MPN 317301200, UPC 999569198382) is the premium bellows-style waste tank discharge pump for marine sanitation systems – the right pump for overboard discharging of holding tank contents in waters where overboard discharge is legally permitted. The T Series is Dometic’s reference-quality pump in this category, designed for both reliability and the specific punishing conditions of marine sanitation service. Two design choices distinguish the T Series from competing macerator-style waste pumps: (1) Bellows-style pump design instead of impeller-type macerator. The bellows pump uses a flexible diaphragm to move waste through the pump body, vs the spinning impeller of competing macerator pumps. Critical practical advantage: the bellows pump can run dry indefinitely without damage – if you accidentally activate the pump on an empty tank, or if the tank empties during pumping while the pump is still running, the bellows pump simply continues running without harm. Impeller-style macerator pumps burn out in seconds when run dry – the impeller depends on water cooling and lubrication during operation, and dry running destroys the impeller and motor within 10-30 seconds. The bellows design eliminates the most common cause of waste pump failure: accidental dry running. (2) Self-priming to 10 feet (3.3 meters) of suction lift – the pump can pull waste up from a holding tank that’s positioned up to 10 feet below the pump location. Critical for boats where the holding tank is in a low bilge area and the pump must be mounted at a higher accessible location. Most competing waste pumps need to be installed at or below the tank level, which limits installation options. 300 gallons per hour (1136 lph) flow rate – empties a typical 30-gallon holding tank in about 6 minutes. Draws only 6 amps at 12V DC – well within typical marine electrical system capacity, can run from the house battery without significant capacity impact. Integrates with Dometic Tank Discharge (DTD) control systems (sold separately) for completely automated holding tank discharge – the DTD system monitors tank level and automatically discharges at programmed conditions or operator command, taking the manual button-pushing out of waste management. 1-year warranty.
The Dometic SeaLand T Series Waste Discharge Pump is the premium bellows-style waste tank discharge pump for marine sanitation systems. It’s the right pump for overboard discharging of holding tank contents in waters where overboard discharge is legally permitted. The T Series is Dometic’s reference-quality pump in this category.
What this pump does. Marine sanitation systems collect waste from the boat’s heads (toilets) in a holding tank below the deck. The holding tank must eventually be emptied – either by pump-out at a marina pump-out station (the legally required method in most coastal US waters where overboard discharge is prohibited), or by overboard discharge in waters where it’s legally permitted (offshore waters beyond the 3-mile US territorial limit, or specific designated areas where overboard discharge is allowed). The T Series pump is the device that empties the holding tank overboard – sucks waste out of the tank and pumps it out through a through-hull fitting. Critical legal note: overboard discharge is prohibited in most coastal US waters, designated ‘no discharge zones’ in the Great Lakes and other waters, and within 3 miles of the US coast generally. Make sure you understand the rules in your operating area before using this pump for overboard discharge.
Bellows vs impeller – the critical difference. The T Series uses a bellows-style pump design – a flexible diaphragm moves waste through the pump body via repeated compression / expansion cycles. Competing waste pumps (and most cheaper marine sanitation pumps) use impeller-style macerator design – a spinning impeller (similar to a small chopping blade) macerates the waste and pushes it through the pump. The bellows design has one critical practical advantage that pays for the higher pump cost over the lifetime of the unit: the bellows pump can run dry indefinitely without damage. If you accidentally activate the pump on an empty tank, or if the tank empties during pumping while the pump is still running, the bellows pump simply continues running without harm. Impeller-style macerator pumps burn out in seconds when run dry – the impeller depends on water cooling and lubrication during operation, and dry running destroys the impeller and motor within 10-30 seconds. Dry running is the single most common cause of waste pump failure in marine service – the pump runs until the tank empties, the operator gets distracted, and the pump burns out shortly after. The T Series eliminates this entire failure mode.
Self-priming to 10 feet. The T Series can pull waste up from a holding tank that’s positioned up to 10 feet below the pump location. Most competing waste pumps can self-prime only 2-4 feet, which limits installation options – the pump must be mounted at or below the tank level for those pumps to function. The 10 ft self-priming capability lets you mount the T Series in a higher accessible location (above the engine compartment, in a utility space) while the holding tank stays in the typical low-bilge location. Practical benefit: easier servicing of the pump (you’re not crawling into the bilge to access it) and more flexible install routing.
300 gph flow rate. The pump delivers 300 gallons per hour (1136 lph) actual flow rate in waste service. Practical translation: a typical 30-gallon holding tank empties in about 6 minutes of continuous pump operation. A larger 50-gallon tank empties in about 10 minutes. The 300 gph rating is sized appropriately for typical recreational and small commercial marine sanitation applications – high enough flow rate to empty the tank quickly without being so high that the pump overwhelms the discharge piping. For very large yachts with larger tanks, multiple T Series pumps in parallel or larger commercial pumps may be appropriate.
Low 6 amp current draw. The T Series draws only 6 amps at 12V DC during operation – well within typical marine electrical system capacity. The low draw matters because pump operation can last several minutes per cycle, and during cycle the pump pulls a continuous current from the house battery. At 6 amps, a 10-minute pump cycle consumes 1 amp-hour from the battery – negligible impact on a typical 200-300 Ah house bank. Higher-current competing pumps (some draw 15-25 amps) can stress smaller battery banks during operation.
Dometic Tank Discharge (DTD) integration. The T Series integrates with Dometic Tank Discharge control systems (sold separately) for completely automated holding tank discharge. The DTD system monitors tank level via electronic sensors and automatically activates the discharge pump at programmed conditions or by operator command. Practical benefit: no need to manually check tank level and manually run the pump. The DTD takes the workload out of waste management entirely. For boats that regularly use overboard discharge in legal-discharge waters (offshore cruising boats, etc.), the DTD upgrade is a meaningful convenience. The DTD is purchased separately from the pump and requires the pump to be installed and wired into the system.
Install. Plan for 3-5 hours for an experienced installer. Tasks: (1) Mount the pump – the pump can mount in any orientation (the bellows design isn’t sensitive to mounting angle) at a convenient accessible location. Use stainless mounting hardware and proper backing under the mounting surface. (2) Plumb the suction line from the holding tank to the pump inlet – use marine sanitation hose rated for waste service (NOT generic water hose – waste hose has specific gas permeation ratings and chemical resistance). The 10 ft self-priming capability gives you flexibility on suction routing. (3) Plumb the discharge line from the pump outlet to the through-hull discharge fitting – again, marine sanitation hose only. (4) Wire 12V power from the boat’s electrical system to the pump through an appropriately-sized fuse (15A is the standard recommendation), with a control switch at a convenient operator position. (5) For DTD integration, wire the pump control through the DTD module instead of directly to a switch.
Sanitation hose – critical. The hose between the holding tank, the pump, and the through-hull discharge fitting MUST be marine sanitation hose specifically rated for waste service. Generic water hose, fuel hose, or hardware-store rubber hose ALL fail in waste service – they permeate gas (allowing the rotten-egg hydrogen sulfide smell from the holding tank to permeate into the boat), they chemically degrade over time, and they collapse under suction. Marine sanitation hose is specifically engineered for waste service with proper gas-permeation barriers and chemical resistance. The pump doesn’t include hose – you supply the appropriate sanitation hose for your specific routing.
What’s NOT included. The pump ships as the pump unit itself plus mounting hardware. NOT included: sanitation hose (supply separately based on your routing needs – typically 50-100 ft of 1.5 inch sanitation hose for a typical install), through-hull discharge fitting (you supply or use existing), control switch and wiring (you supply based on your install), DTD module (sold separately for automated control), and any plumbing fittings for the specific install.
Important legal warning. Overboard waste discharge is prohibited in most coastal US waters, in designated ‘no discharge zones’ in the Great Lakes and inland waters, and generally within 3 miles of the US coast. The T Series pump is a tool that’s legal to install and own. the legal question is when and where you operate it. Make sure you understand the rules in your operating area before discharging overboard – violations can result in significant fines. For boats operating primarily in waters where overboard discharge is prohibited, a Y-valve can route the pump output to either the through-hull discharge (for legal-discharge waters) or to a pump-out fitting (for marina pump-out service in no-discharge waters). Many serious cruising boats install this dual configuration for flexibility.
Warranty. Dometic 1-year limited warranty applies. Save the receipt and the original packaging. Warranty service runs through Dometic’s authorized service network. Note that this product cannot be returned to the original point of purchase per Dometic policy – contact the manufacturer directly with any warranty issues. Most field failures Dometic sees in the T Series are install-related (wrong hose, dry-run impossible since it’s a bellows pump, incorrect wire size causing voltage drop) – the pump itself is exceptionally reliable when properly installed.
