Waterpik Aquarius WP-660: problems, parts and running costs

Checked: 2026-10-08

Summary

The WP-660 is a corded countertop water flosser with 10 pressure settings, a 22 oz reservoir and a 3-year warranty, and the complaints that come up most often are physical rather than performance-related: pump noise up to 72 dB, hose and handle leaks, and mold around the handle and inside the housing. The running cost is replacement tips every 3 to 6 months plus an occasional hose or handle, with electricity negligible and no subscription. It is a strong buy at $70 or less, still reasonable up to $90, and above $110 the bulk and the noise start to cost more than the feature set is worth.

Common problems and fixes

Noise — Electric Teeth measured up to 72 dB and called it pretty average rather than ultra quiet, while Dentaly.org rates sound poorly and quotes users describing it as insanely loud; noise rises with the pressure setting. There is no repair for it, so turn the setting down or move to a cordless unit. [2][3]
Hose and handle leaks — a long r/BuyItForLife thread describes the hose developing a hole, a replacement hose and handle lasting only 2 months, and then the machine leaking from the bottom; r/fixit threads cover leaks at the base of the handle, and commenters recommend a full handle-and-hose assembly and warn against cheap aftermarket hoses. The manual says to contact the Waterpik service center when the hose leaks, and a worn hose is not a manufacturing defect, so the 3-year warranty is unlikely to cover it. [4][5][6]
Motor failure and no water ejected — r/fixit threads report a unit with the power light on but no water, and one owner revived a dead unit by disassembling it and lubricating the motor. Waterpik states the unit has no consumer-serviceable electrical parts and that opening it voids the warranty, so treat this as a warranty case rather than a repair job. [7][8][6]
Tubing snapping inside the wand — a r/fixit thread shows the tubing snapping cleanly. The route is the same as for a leaking hose: Waterpik-approved parts through the service center, because the company states it does not guarantee the availability of replacement parts or repair services. [9][6]
Messy first weeks — new users spray water across the sink until they learn to lean over it, start at a low pressure setting and close their lips around the tip; most owners settle around level 7. Nothing breaks, it is a learning curve. [2][3]
Countertop bulk and a lid that will not quite seal — some users find the footprint too large for a small bathroom, the reservoir lid can be tricky to seal fully, and the unit is not portable, not waterproof and cannot be used in the shower. Check the counter space and the outlet position before buying. [2][3][1]

Parts and consumables

Replacement tips (JT-100E Precision, OD-100E Orthodontic, PS-100E Plaque Seeker, PP-100E Pik Pocket) — about $5 per nozzle at Electric Teeth (February 2024) and $14.99 for a 2-pack at MedGrade (April 2026); owners replace them every 3 to 6 months. [2][10]
Optional tips that are not in the box — the TB-100E toothbrush tip, DT-100E implant denture tip, TC-100E tongue cleaner and the tip storage case ship with the WP-670 Professional rather than the WP-660, and are sold separately. [1][15]

Yearly running cost

Tips are the only scheduled cost. Electric Teeth budgets about $5 per nozzle and about $95 of nozzles over 3 years; MedGrade prices a 2-pack at $14.99 and puts the yearly spend at $159.95 including the device, so for a buyer who already owns the unit the tips are the recurring line. Since tips are swapped every 3 to 6 months, a year takes at least two sets. Everything else is occasional: a replacement hose or handle after a leak, descaler and vinegar for the reservoir, and electricity on a 120 V unit, which is negligible. There is no filter, no capsule and no subscription. [2][10][3]

When it is a good buy

At $70 or less the WP-660 is a strong buy: the clinical evidence, the ADA Seal of Acceptance, 10 pressure settings from 10 to 100 PSI, 7 included tips and a 3-year warranty are hard to match. Between $71 and $90 it is still good value if you want clinical efficacy and tip variety over portability, from $91 to $110 it is fair against cordless units, and above $110 the bulk and the noise eat into the value. Waterpik’s own store listed it at $59.99 to $79.99 on sale against a $99.99 MSRP (Waterpik store, October 2026), Consumer Reports lists it at $54.99, and Electric Teeth puts a fair price around $80 against $99.99 retail. Two named alternatives: the cordless Waterpik Ion, Wirecutter’s top pick, is the better choice when quiet, portability and travel matter more than the 22 oz reservoir and the pressure range; the WP-670 Aquarius Professional performs identically and is the better choice if you want the toothbrush tip and the tip storage case in the box. [2][3][12][13][14][15][1]