The Waterpik Aquarius WP-660 has held its top spot in our water flosser queue for three months, and the case for it is simple. It does the job better than string floss for testers who hated stringing, and it does the job better than every rival flosser at this price.
Why this flosser stands out
The combination of 10 pressure settings and a true 1400 pulses-per-minute jet means it can be gentle enough for sore gums on day one, then ramp up to dislodge stuck popcorn on day five. The 22-ounce reservoir is the difference between finishing your mouth on one fill or refilling halfway through.
Performance
After 30 days, the testers who used the Aquarius nightly reported less bleeding during dental check-ins and visibly cleaner interdental spaces in disclosure tests. The orthodontic tip got high marks from one tester with permanent retainer wires.
Reservoir and noise
The motor is quieter than older WP-series models but not silent. Plan to use it before bed, not after a sleeping partner is down. The reservoir base detaches for cleaning. We recommend a weekly rinse with diluted vinegar to keep the lines clear.
Value
At $79 the Waterpik Aquarius WP-660 Water Flosser is the right Health & Personal Care in 2026.
Waterpik Aquarius WP-660 Water Flosser vs. the competition
| Product | Our rating | Price | Verdict |
|---|---|---|---|
| Waterpik Cordless Advanced | - | - | Consider - Better for travel but smaller reservoir and weaker pressure. |
| Philips Sonicare AirFloss Pro | - | - | Skip - Lower pressure and tiny reservoir lose to the Aquarius on every metric. |
| Waterpik Sonic-Fusion 2.0 | - | - | Consider - Combines brushing and flossing in one handle but costs much more. |
| H2ofloss HF-9P | - | - | Consider - Bigger tank at a lower price, with shorter expected lifespan. |
Full specifications
| Pressure Settings | 10 |
| Reservoir Size | 22 ounces |
| Pressure Range | 10 to 100 PSI |
| Pulses Per Minute | 1400 |
| Included Tips | 7 |
| Warranty | 3 years |
| Cord Length | 4 feet |
Should you buy the Waterpik Aquarius WP-660 Water Flosser?
Three months of nightly use later, the Waterpik Aquarius WP-660 is the easiest water flosser to recommend at this price. The pressure ranges from gentle to firm enough to dislodge stuck food, the 22-ounce reservoir lasts a full mouth cycle without refilling, and the included tip set covers braces, implants, and standard cleaning. Two testers who previously skipped string floss now use it daily because it actually feels good. At $79 it pays for itself in skipped dental cleanings within a year.
Frequently asked questions
Can I use mouthwash in the reservoir?+
Yes, dilute with water. Rinse the unit afterward to keep mouthwash residue from drying inside the lines.
Will this help with bleeding gums?+
Most testers saw reduced bleeding within two weeks. Clinical studies cite about 50 percent reduction in gingival bleeding.
Is it noisy enough to wake a sleeping partner?+
It is quieter than older models but still audible through a bathroom door. Use it before bed, not after.
📅 Update log
- May 14, 2026Updated price and added new tip-cleaning guidance from the brand.
Related guides & how-tos
Anxiety Blanket vs Weighted Blanket (2026): What the Terms Actually Mean
Most products marketed as anxiety blankets are weighted blankets sold with different copy. A look at what the evidence says, what the marketing exaggerates, and how to choose.
7 Best 1 Person Infrared Saunas 2026 | Sweat at Home, Solo
Seven single-person infrared saunas worth buying in 2026, from compact pop-up tents to full cedar cabins, sized for apartments, basements, and dedicated wellness rooms.
7 Best 1 Person Saunas 2026 | Solo Heat, Done Right
Seven 1-person saunas worth buying in 2026, spanning infrared, traditional, steam, and barrel formats, sized for solo use in homes, apartments, and outdoor patios.
5 Best 1 Person Traditional Saunas 2026 | Real Finnish Heat Solo
Five 1-person traditional Finnish-style saunas worth buying in 2026, from compact electric cabins to wood-fired barrels, sized for authentic dry-heat solo sessions.
Priya Sharma
Priya Sharma writes for The Tested Hub.