Every drain cleaning machine gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Machines are grouped by line size: a machine sold with a cable of 3/8 in or thinner is a small line machine, and one sold with a 1/2 in cable or thicker is a main line machine. A machine sold without cable goes by the largest drain its maker rates it for, with 4 in and up counted as main lines. Motor, features and warranty use the same scales in both groups; price and cable use a scale for each group.
| Factor | Measures | Weight |
|---|---|---|
| Price | price of the machine as sold | 25% |
| Cable | length times diameter of the included cable | 25% |
| Motor | motor power in watts | 10% |
| Features | auto feed, foot switch, reverse and included cutters | 20% |
| Warranty | warranty length | 20% |
Where the numbers come from
Cable, motor, features and warranty come from the maker’s product page, spec sheet or operator’s manual, or the maker’s own copy on a retail listing. Where a maker gives motor power in horsepower, it’s converted to watts at 746 W per hp. Prices are checked at Amazon, the maker’s own store and other stores that sell the machine new, and the lowest price at a store the page links to is used.
The factors
Price is the current price, on a log scale, so halving the price always counts the same. For small line machines, $1,500 scores zero and $250 full marks. For main line machines, $5,000 scores zero and $300 full marks.
Cable is the length of the included cable times its diameter, in foot-inches, so 100 ft of 1/2 in cable counts as 50. A thicker cable carries more torque and a longer one reaches further, and both matter. For small line machines, 5 scores zero and 38 full marks. For main line machines, 25 scores zero and 80 full marks. A machine sold without cable scores zero here.
Motor is the motor’s power, on a log scale: 150 W scores zero and 750 W full marks.
Features is 35% for auto feed, 25% for a foot switch, 20% for reverse and 20% for included cutters.
Warranty is the maker’s warranty: 1 year scores zero and 5 years full marks. A lifetime warranty counts as full marks.
What isn’t scored
Rated drain sizes, cable speed, weight, voltage, battery power, and whether the machine is a drum or sectional machine are listed but not scored. Budget listings often quote motor speed of 1,700 to 1,850 rpm, which is not the speed the cable turns, and pipe ranges far wider than their cable is made for, so neither is used.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Features score neutral only when none of the four is published; a feature the maker doesn’t mention otherwise counts as absent. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as the shortest warranty on the scale, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.