Roborock S8 Max Ultra: problems, parts and running costs

Checked: 2026-10-20

Summary

Owners of the Roborock S8 Max Ultra report recurring dock water-handling faults, charging-contact failures and a mop heater that stopped working, with parts support described as limited after about 1.5 years. Running costs are consumables only, with the product page listing 480 ml floor cleaning solution at $18.99, a 6-piece dust bag at $25.59, side brushes at $15.99 and a cleaning brush at $19.99 [5]. It is a good buy only at a steep discount, in the $614.99 to $799.99 band, and only for buyers who do not want a camera in the home; above about $1,000 it is not defensible against the camera-equipped S8 MaxV Ultra [1][19][20][21].

Common problems and fixes

Error 44 dirty-water-tank overflow — reported on every job by zone and by room, with water from the base running onto the floor; workaround is Settings > Dock Settings > Dock Maintenance > Pump, which drained the base; the owner called it a “$1200 piece of shit” after one year of use. [9]
Error 104 main brush open circuit — persists after troubleshooting; the owner could not remove the robot’s top cover because there were no additional screws to remove. [8]
Dock replaced entirely — one owner reported the dock “had to be replaced”. [12]
Charging-contact failure and wet warranty return — a docking/charging contact failure required warranty service, and the returned unit arrived wet, water-stained, musty smelling and more damaged than when shipped. [11]
Mop heater stopped working — stopped after some months of use; the same owner reported the machine “died from litter”. [13]
New unit would not power on — a brand-new unit was unresponsive, with all three lights blinking when docked. [14]
Side brush motor failure — required disassembly; the VibraRise mopping module “keeps sagging” after reassembly. [15]
Detergent dispenser never empties — the container was still nearly full after six months, with no visible setting to enable it. [16]
No parts support after 1.5 years — a 1.5-year-old unit failed and customer service asked for a return, offering no part number or source. [10]
Rubber piece stuck under the dock mop cleaning brush — support did not answer the question and instead asked for the whole unit to be sent back. [17]

Parts and consumables

Floor cleaning solution (480 ml) — $18.99 at the Roborock US store; the 580 ml detergent tank is rated for over 3 months of use. [5]
Dust bag (6-piece pack) — $25.59 at the Roborock US store; auto-emptying is rated at 7 weeks between bag changes. [5]
Side brushes — $15.99 at the Roborock US store. [5]
Cleaning brush — $19.99 at the Roborock US store. [5]

Yearly running cost

No subscription is reported. Detergent runs about four bottles a year at $18.99 each, since the 480 ml bottle is rated for over 3 months. Dust bags run about seven a year, with a 6-piece pack at $25.59. Mop cloths, washable filters and brushes add to that, but no prices or replacement intervals for them were confirmed in sources. Electricity use was not quantified. [5]

When it is a good buy

Discounted sightings: $614.99 for the plumbed RDS version [19], $699.97 from $949.99 in a June 2026 price post [20], and $799.99 from $1,299.99 at The Ambient in July 2025 [21]. The Roborock US store lists it at $1,599.99 and shows it as out of stock, coming soon [5]. Above about $1,000 it is not defensible, because the buyer pays S8 MaxV Ultra money for a machine Vacuum Wars could not recommend on measured performance [1]. Alternatives: the S8 MaxV Ultra is the better choice if the budget stretches to about $1,799, since it has 10,000Pa suction, a front camera and better airflow, crevice pickup, carpet deep clean and obstacle avoidance [1][3]. The Dreame X40 Master is the other plumbed option worth comparing for buyers who want automatic refill and drainage [4]. An owner who moved on from a failed S8 Max Ultra reported switching to the Saros 20 Sonic and Saros 10R [13].