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Waterpik WP-660 Aquarius Water Flosser Review

waterpik wp-660 aquarius featured image

Waterpik offers standalone, countertop water flossers or the Complete Care systems that have both a water flosser and electric toothbrush included. The Waterpik WP-660 Aquarius is their most fully-featured water flosser that does not include an electric toothbrush.

The Complete Care systems are intended to be an all-in-one solution for your dental care routine, but if you already own an electric toothbrush then you would be best served by the Aquarius.

Check out our Waterpik overview and comparison if you want to see more information about the different models available.

So what makes the WP-660 Aquarius the best standalone, countertop water flosser?

  • Timer/Pacer Feature to make sure you flosser long enough.
  • Large Water Reservoir – 650 mL or 22 fl. oz.
  • 3 Year Warranty
  • 10 Pressure Settings

Part of water flossing, or brushing, correctly is spending the necessary amount of time to do the job right. For water flossing, Waterpik recommends at least 1 minute with 30 seconds spent on your top and bottom teeth. That’s what the timer and pacer features are for, and they give you the cue to stop brushing and switch sections.

Majority of the Waterpik models come with the 650 mL reservoir or larger, so this isn’t anything special. But it’s a good size, and should last you about 90 seconds on a full tank.

The standalone water flossers typically have 3-year warranties, whereas the Complete Care Systems only have 2-year warranties. This provides a lot of peace of mind.

Pressure settings are probably one the most easily overlooked features unless you’ve used a water flosser before. It’s one of those things that can only be appreciated when you have to make due without it. Majority of the water flossers operate in the same pressure range, 10 to 100 PSI, but some models have 3 pressure settings while others have 10.

The more the better!

Being able to switch to 10 different pressure settings in that range mean you can be sure to find a comfortable setting, whereas having only 3 settings mean you don’t get as much control over the pressure. It’s either going to be too hard or too soft.

What else is unique about the Aquarius?

The Aquarius is the only water flosser that has the timer and pacer features, aside from the WF-05 Whitening model. Not only that but among the standalone countertop water flossers, there is only the WP-100 Ultra, WF-05, and WF-06 Whitening that have 10 pressure settings.

pressure settings chart for waterpik countertop flossers

Not even the Complete Care systems have the timer and pacer features, so if that’s important to you consider just getting a standalone water flosser and picking up a separate electric toothbrush.

Waterpik Water Flossing Replacement Tips

JT-100E Waterpik Classic Jet Tip


JT-100E Classic Jet Tip

General use tip. Cleans between teeth and below the gumline.

OD-100E Waterpik Orthodontic Tip


OD-100E Orthodontic Tip

Tapered brush to reach plaque around orthodontic brackets and wires. It’s significantly easier to clean around braces with these rather than string floss.

Waterpik PS-100E Plaque Seeker Tip


PS-100E Plaque Seeker Tip

For cleaning around implants, crowns, bridges, and other restorations. It has 3 thin tufts of bristles. These have not been shown to be signifcantly more effective than the Classic Jet Tip for plaque removal, but you may find the brush helpful.

PP-100E Waterpik Pik Pocket Tip


PP-100E Pik Pocket Tip

Ideal for periodontal pockets and furcations. It has a soft rubber tip which produces gentle, low pressure.

TB-100E Waterpik Water Flosser Toothbrush Tip


TB-100E Toothbrush Tip

These toothbrush tips don’t spin or vibrate. They’re just stationary brushes to let you brush and floss at the same time.

waterpik tongue cleaner tip example


TC-100E Tongue Cleaner Tip

The tongue scraper also sprays water as you scrape to help flush out bacteria and other compounds that live on the tongue.

Adding Solutions to the Reservoir

You can add mouthwash to your Waterpik with no issues. It is important that you don’t exceed a 1:1 ratio of mouthwash to water no matter what type of mouthwash you use.

  • Standard or Cosmetic Mouthwash
  • Antiseptic Mouthwash (Listerine)
  • Therapeutic Mouth Rinse (Usually prescribed by a dentist.)
  • Bleach or Bleach Solution
  • Essential Oils
  • Salt, iodine, or baking soda

Adding anything other than the mouthwash types listed above can potentially damage your Waterpik either through corrosion or pump failure. Be sure not to add more than a 1:1 ratio of the recommended solutions, as it can damage your Waterpik’s pump. One potential reason for this is a change in viscosity can cause the pump to have to work hard, which over time will wear it out faster.

waterpik reservoir capacity


The older WP-72 Classic Pro is the largest capacity Waterpik available. However, it doesn’t have a lid on the reservoir, which some people don’t like. The Aquarius has more than enough water capacity for a full 1-minute flossing session, so the extra capacity isn’t as useful as it seems.

The travel-friendly WF-04 Sidekick has the smallest capacity and also has no lid. It’s the more recent travel-sized model and is an upgrade to the WP-300 Traveler.

Frequently Asked Questions

Q: How long is the water hose?

A: You can extend it about 30 inches.

Q: How long is the power cord?

A: 53 Inches

Q: Can I plug the WP-660 into a 220V outlet with a voltage converter?

A: There is a high likelihood you will damage the unit. It’s best to buy a global voltage model or buy from a distributor in your country. The WF-04 Sidekick is a global voltage model.

Q: Can I put the water reservoir in my dishwasher?

A: Yes, but be sure it’s on the top rack. It’s best not to run it through the heated dry cycle, and instead, just air dry it.

Q: Is the warranty still valid if I purchase a Waterpik from Amazon?

A: Yes, Amazon is an authorized retailer for Waterpik products.

Q: Where is the Waterpik WP-660 Aquarius made?

A: Designed in the USA. Made in China.

Cleaning and Maintenance

There are a few things you need to do to keep your Waterpik clean and pumping at full capacity. Minerals from your water can build up in the lines and cause reduced flow.

Follow these steps if you notice reduced flow or want to do routine preventative cleaning.

  1. Mix 2-4 tablespoons (1-2 ounces) of white vinegar with 16 ounces of warm water.
  2. Fill the reservoir with the solution, and then run 1/2 of it through the Water Flosser.
  3. With the unit off, place the Water Flosser handle in the sink and allow the solution to drain out of the handle gradually.
  4. Run any remaining solution through the unit and then rinse with a full reservoir of warm water.

You also need to clean the flosser tips and handle. You can let them sit in distilled white vinegar or hydrogen peroxide for 5-7 minutes. This won’t damage the handle.

Doing this cleaning routine monthly is best, but you definitely will want to do it at least every 3 months.

Still Undecided?

Check out our overview of the entire Waterpik product lineup. You can get a look at the big picture and decide on the right water flosser for you.


Pressure Range:10 to 100 PSI (0.703 to 7.030 Kg/cm2)
Flow Rate per Minute:13 Ounces (400 mL)
Pulses per Minute:1400
Number of Pressure Settings:10
Included Flosser Tips:7
Water On/Off Switch on Handle:On/Off Slider
Chrome Accents:No
Rotating Tip:360 Degree
Whitening Handle:No
Massage Mode:Yes
LED Function Indicator:Yes
Capacity:22 Ounces (650 mL)
Capacity in Seconds:90
Medicament Reservoir Included:No
Height (with Tip/Brush):10.35 Inches (26.29 cm)
Max Width (Base):4.70 Inches (11.93 cm)
Max Depth (Base):3.80 Inches (9.65 cm)
Unit Weight:1.46 Lbs (0.665 kg)
Shipping Weight:2.00 Lbs (0.910 kg)
Voltage:North America only; 120VAC/60Hz
Warranty:36 Months