Home Blog Buyer's Guides How Long Does Zerowater Filter Last and Why the Water Tastes Lemony?

How Long Does Zerowater Filter Last and Why the Water Tastes Lemony?

par Dr. Jonathan Doyle - Updated March 11, 2021
The water filter pitcher is one of the most popular filtration options on the market for its accessibility and convenience. Many consumers purchase the water filter pitcher to reduce unpleasant flavors and odors, and wish to improve the water quality.
Among all kinds of pitchers with different designs and filtration performances, the ZeroWater filter pitchers stand out for their ability to reduce the TDS (total dissolved solids) to zero.
ZeroWater Pitcher in the refrigerator
Yet, behind the successful marketing concept, the product receives numerous complaints about its taste and replacement cost. Before making the purchase, let’s take a thorough look at the ZeroWater pitcher. We’ll ask how long does the ZeroWater filter last, and why does the water taste lemony?

The unpleasant taste within a very short time

Based on many reviews and product comparison reports, the water filtered by ZeroWater tastes better than that of Brita and PUR water filter pitchers. However, consumers complain that after about two weeks, the water developed a very unpleasant taste. Some people described it as a sour and lemony disgusting taste, some people described it as fishy.
A female looks doubtful to the glass of water she’s holding
The reason for the sour chemical taste is not because of some flaws of the product quality, but the urgency to replace the filter. Why? How long does a ZeroWater filter last? The following section will explain the filtration process behind and answer the question for you.
ZeroWater uses ion exchange to reduce the TDS in water to zero. The ions carrying positive charges are called cations, while ions carrying negative charges are called anions. The two types of ions in water are always equal in the number of charges.
Typical cations may include calcium ion, sodium ion, potassium ion, magnesium ion, and typical anions may include sulfate ion, chloride ion, carbonate ion, and so on. The ZeroWater filter contains an ion exchange layer that replaces the cations with hydrogen ion, and replaces the anions with hydroxyl ion, which forms pure water H2O eventually.
The filter will work perfectly to deliver you pure water until it runs out either H+ or OH-. If the OH- is fully consumed first, then the anions remain in the water after filtering, and the cations are still replaced by the hydrogen ion (acid ion), finally resulting in acids, such as sulphuric acid, hydrochloric acid, and carbonic acid. That's why the water tastes sour or acidic at the end.

The high replacement cost

You can solve the unpleasant taste problem simply by changing the filter. Then the next problem shows up: the frequency of filter replacement. Like we have discussed above, once the H+ or OH- inside a filter runs out, then it’s time to replace. So how long does a ZeroWater filter last? Not very long. We’ll go into more depth below.
Coins stacking up
Based on the true product reviews, if the source water TDS is around 100, the ZeroWater filter can filter about 15-18 gallons of water before it turns sour. If the source water has high TDS as 700, each ZeroWater cartridge could not filter more than 5 gallons of water.
So, how long does a ZeroWater filter last? The numbers are far below than the advertised filter service life. A filter will last, on average less than two weeks.
Therefore, it could become excessively pricey having to change the filter three times a month. It would be economically preferable to switch to other filtration options.

What is TDS and how to reduce TDS in water?

Before we jump into the filtration option section, let’s learn some information about the TDS.
TDS stands for total dissolved solids, it refers to the total concentration of dissolved solids in water including both inorganic and organic matters. Some of the common components are calcium, magnesium, sodium, and potassium cations and carbonate, hydrogen carbonate, chloride, sulfate, and nitrate anions.
There is no scientific evidence that suggests that high TDS will bring out adverse health effects. Many countries do have drinking water standards in regards to TDS, but only for aesthetic reasons with no health criteria. The US recommended maximum level is 500 mg/L as well as the Canadian guideline. To learn more about the recommended TDS level here.
TDS Level in parts per million(ppm) Palatability Quotient
Less than 300 Excellent
Between 300 and 600 Good
Between 600 and 900 Fair
Between 900 and 1200 Poor
Greater than 1200 Unacceptable

Efficient and economical way to reduce the TDS in water

The common ways to reduce the TDS in water are distillation and reverse osmosis


Distillation offers clean water through boiling and producing water vapor. When water vapor rises and reaches to a cool surface, it will condense back to the liquid form. The dissolved salts and other particles will remain in the boiling solution.
The distillation process
You can get zero TDS water from distillation without the concern to replace any filters, however, the downsides are the energy cost and the slow output.

Reverse Osmosis

The benefits of Reverse Osmosis filtration is obvious by comparison. The system uses a semi-permeable membrane which the unclean water is “pressured through.”
The membrane contains pores of 0.0001 microns that are only big enough to allow the passage of water molecules while blocking other foreign components like pyrogens, bacteria, organics, and dissolved solids. The normal output of a RO system is around 200-600 gallons per day and you can access clean and safe water by just turning on the faucet.
Therefore, from the efficiency, sustainability and cost perspectives, we recommend using a reverse osmosis system to reduce the TDS in water. Many people are concerned about the amount of waste water that the RO system generated during the filtration process.

Our recommendations

Below are several types of RO systems from Waterdrop that we have picked for you. These systems have a low drain ratio of 1:1, meaning for every gallon of purified water, the system only produces one gallon of waste water.
As the star product of Waterdrop, the G3 reverse osmosis is taking the market by storm with its revolutionary tankless design. The system looks nothing like a traditional RO system. It is very thin and sleek. The tankless design saves much undersink space and brings more room for storage.
In terms of filtration performance, the G3 system adopts the premium DOW RO membrane with the TDS removal rate of 94% as well as other contaminants in water.
The system is designed for easy DIY installation and the filter replacement only takes 3 seconds. If you’re looking for an efficient and certain way to get clean, safe and healthy drinking water, Waterdrop G3 would be the ideal option.
The Waterdrop M5 reverse osmosis system is a countertop RO system. Besides the benefits of a RO system, the highlight of this product is the portable water pitcher that is made of high-quality Tritan plastic. If you don’t know Tritan plastic, it is a BPA-free plastic that is widely used in food containers or feeding bottles. The Tritan plastic is as clear as glass but much lighter.
With a water storage tank like this, you can enjoy clean water at any time without waiting. The pitcher can also be placed into the refrigerator if you prefer the cooling taste.
The Waterdrop G2-P600 reverse osmosis system is another great reverse osmosis system with its fast output of 600 GPD(gallons per day) and a low drain ratio of 2:1. The high efficiency brings 2 cups of pure water with only one cup of waste water.
Compared with the G3 model, the system takes fewer undersink space and faster water output, but it does not carry all the fancy features that G3 contains. For example, real-time TDS reading.
If you want a tankless design RO system that generates a small amount of waste water, the G2-P600 would be a very cost-effective choice.