Tips for Taps Blog

Testing Your Tap Water–Cheaper and Better Than Bottled Water

Testing Your Tap Water–Cheaper and Better Than Bottled Water


Is coronavirus impacting your tap water? Your home’s water quality depends on many factors, but coronavirus doesn’t appear to be one of them…

SimpleLab wrote this article in partnership with the Environmental Policy Innovation Center to discuss the case for testing and using tap water over bottled water during the coronavirus crisis.

We understand that you might fear unsafe tap water amidst the unfolding health crisis around us. You may feel safer buying bottled water than drinking your tap water. But bottled water should only be an alternative to the tap if you discover your water is unsafe and you’re in the process of purchasing a filter.

All evidence points to the fact that COVID-19, the disease caused by the novel coronavirus, is not transmitted through water (see the updates on Centers for Disease Control and Prevention). Even if it were transmitted through water, our public water suppliers have systems in place to destroy viruses, such as the novel coronavirus. 

Below we’ll cover the state of American public water systems, evidence from Tap Score household water data, and a cost evaluation which concludes: Tap water wins out over bottled water, almost every time.

Save money by skipping bottled water and choosing to test, treat, and trust your tap. Skip the trip to the store and slow the spread of COVID-19.

Effective Treatment and Better Monitoring 

Coronavirus isn’t in your drinking water 

Coronavirus has not been identified in water sources or drinking water supplies. And even if it were, water systems are well equipped to treat the water. This is likely the case for recycled water as well. Most water systems require multi-step treatments including filtration and disinfection. These processes effectively eliminate viruses up to 99.9%–that’s pretty much the most certainty you’ll find in any scientific process. The World Health Organization states that coronavirus would be removed even faster than viruses like  adenoviruses, norovirus, rotavirus and hepatitis A because of its fragile outer membrane. 

While most bottled water suppliers will also treat water to effectively kill viruses, they are not held to the same water quality testing standards as tap water.  “Bottled water is not free of contaminants,” noted Dr. Carsten Prasse, an assistant professor of Environmental Health & Engineering at the Johns Hopkins University and scientific advisor at SimpleLab. “In addition to those that might be present in the water itself, chemicals such as plasticizers can also leach out of the plastic into the water and have adverse health impacts–for example they can impact our hormonal system.” This means that bottled water is tested with less oversight than your public water supply and may have additional risks.

Testing Equals Trust 

Tap Score home water tests give insight into municipal water quality

Tap Score has been testing household (and commercial) tap water for the last three years, building up a unique understanding of water quality across U.S. states. Tap Score data insights dispel the myth that all tap water is risky and that bottled water is a necessity. 

Of the Tap Score households who explicitly tested city water and tested enough parameters to receive a Tap Score, 38% of households received an A- (90%) or higher. Of these households, 81% received a solid A (94+). Our sample is not representative of the U.S., but these tests reflect that households interested in testing their tap water often confirm that they can trust their tap water with regular testing.

Tap water quality depends not only on the public water treatment, but also on household plumbing materials, the age of pipes, and a variety of other factors. We find that many household tests for contaminants like lead or trihalomethanes come up as “non-detects”–in other words, they are not found in municipally treated tap water.

Dose makes the poison: most detections are very low in municipal tap water

Tap Score tests are performed in certified labs using advanced analytical methods, which can detect even trace concentrations of contaminants. Not every detection is equal. Most detections are at low concentrations, which often pose no measurable health risk for consumption. While low concentrations of some contaminants can be a serious concern over a lifetime of exposure– much of this risk can be mitigated with affordable home water treatment. 

Figure 1 shows the percentage of households that found something in their drinking water but found it was BELOW stringent health thresholds (public health goals) or aesthetic thresholds (for Iron and Sulfate). This is based on thousands of tests since 2017. As you can tell, nearly all the glasses are FULL – meaning most detections were below concerning health levels.

Contaminants in city water

Figure 1. Percentage of households that detected a contaminant and found it was BELOW stringent public health or aesthetic thresholds.

When Tap Score users do find concerning water quality problems at the tap, affordable treatment options cheaper than bottled water almost always exist. Every tap is unique, but solutions are frequently easy to identify. 

Now more than ever, our communities need to rely on tap water to skip any unnecessary trips (e.g. to buy bottled water). Almost all states have a shelter in place order to prevent the spread of COVID-19.

We compared Tap Score home water tests before and during coronavirus 

Are you worried that coronavirus has worsened water quality? From our data, we see no evidence to suggest that city water quality is worse now that coronavirus has plagued communities across the country. Tap Score tests in February and March of 2020 do not demonstrate higher detection rates when compared to those from February and March of 2019 (Table 1).

Tap Score users hail from all over the U.S., and contaminant concentrations in tap water vary across geography and time. No two taps are alike, so Table 1 is not comparing “apples to apples” or “taps to taps” between the two time periods. What Table 1 does suggest is that while there is variability across the two time periods, there is no indication that water quality is getting worse on the whole. If anything, Tap Score home water testing in 2020 demonstrated somewhat improved water quality relative to 2019 (at least among these 9 basic contaminants for people using Tap Score). 

Table 1. Tap Score home test detections before and during coronavirus spread.

Water parameters

Testing and Filtration Cost Less Than Bottled Water

Even a contaminated or bad tasting tap will cost you less to fix than bottled water

For those people that do find concerning contaminants in their city water, point-of-use treatment is an effective and affordable option. Still many of you might already trust your tap but simply dislike the taste or smell of your tap water. Testing and filtration can deal with these challenges for less money and less environmental impact than bottled water. 

Let’s do the math. We’re going to assume that the average household is about 3 people, and that each person needs 2 liters of drinking water per day, or 0.53 gallons per day. That’s equivalent to ~580 gallons per year–just for drinking water. This fluctuates by age, gender, and activity level, but overall this is a pretty minimal amount of water compared to other household uses (like flushing the toilet). So what does this cost? 

Annual cost of water

How we estimated numbers for this infographic: 

Tap: Estimated based on average cost of $0.0034 per gallon based on average water rates

Tap + Pitcher: Estimated based on average cost of $0.0034 per gallon + $40 average pitcher cost over 10 years of use ($0.40/year) + average annual maintenance cost around $105 based on average cost break-downs

Tap + Reverse Osmosis: Estimated based on average cost of $0.0034 per gallon + $300 average system cost over 10 years of use ($30/year) + average annual maintenance cost around + average annual maintenance cost around $130 based on average cost break-downs

Bottled Water: Estimated based on average cost of bottled water of $3.84 per gallon (assuming $0.03/oz as the middle of the road choice for bottled water in bulk on Amazon).

Taking data on U.S. water rates and bottled water from a variety of sources, our quick back-of-the-envelope estimates show that the cost of filtered tap water for a 3 person household is quite literally hundreds to thousands of dollars less per year compared with bottled water. The cost of tap water water ranges from $0.58 to $4.35 per year on a volumetric basis based on the minimum and maximum water rates estimated in the U.S. in 2016 ($0.001 per gallon to $0.0075 per gallon). While your water bill is likely much higher than $2 per year, this is due to fixed fees, water consumed for other purposes (showers, toilets, watering the lawn) and sewer costs. These costs aren’t included in our comparison because you have to pay that bill to keep the toilets flushing and showers running even if your main drinking water choice is bottled water.

If your tap water has concerning levels of any contaminant, at-home filtration adds costs to your typical tap water. There is a wide range of options for at-home filtration. Cost break-downs depend greatly on the type of filter and whether you treat your whole house or a single tap; for our estimates we assume single-tap treatment and an upfront capital cost that can be spread out over 10 years of use. Basic filters carbon filter pitchers cost $20 to $50 up for the pitcher, with $60-$150 per year in maintenance costs. Advanced reverse osmosis (RO) systems for under-the-sink are usually required where water quality is particularly bad; these can run anywhere from $100 to $500 with $60 to $200 in annual maintenance costs. High end expensive RO systems are rarely needed if you rely on city water, but even these run cheaper than bottled water.

Bottled water costs can range pretty dramatically, but they are almost always expensive. We found a bulk-purchase cost of single-serve bottles and larger jugs on Amazon ranging from $1.28 per gallon to $6.40 per gallon (with the average being around $3.84 per gallon), as well as a reported average cost of top bottled water retailers of $9.47 per gallon. This means bottled water for a family of three could cost anywhere between $740 and $5,490 per year! Even water kiosks – like the kind you can get at your grocery store or in a parking lot – are less economical than they appear. At $0.25 per gallon, a year’s supply of kiosk water would put a 3 person family out for $145 per year. When you add on 2 reusable 5-gallon jugs ($15 each) that should be replaced every 50-100 uses, this adds up to about $175 per year.

Bottled water costs more to society and the earth

In 2018, the U.S. bought and purchased 13.8 billion gallons of bottled water, with a majority of people (65%) buying single-use bottles. The tragedy here is that plastic bottles are a huge burden on the environment compared with tap water. Bottled water production and disposal increases greenhouse gas emissions that contribute to climate change. Bottled water companies often deplete and drain freshwater resources from local communities. And plastic bottle waste contributes to the build up of plastics and leaching chemicals in our oceans.

Skip the Trip, Trust your Tap

Bottled water is expensive, extremely unsustainable and not even held to the same stringent water quality testing standards as tap water. Moreover, massive federal funding to keep water systems strong through coronavirus and beyond is likely coming this year. Skip the trip and test your tap to ensure you have safe water quality. If you don’t, SimpleLab can provide easy and unbiased recommendations for cost-effective water treatment at home.

About the Authors

Jess Goddard, PhD is Chief Science Officer at SimpleLab, where she oversees water research and data science.

Timothy Male, PhD is Executive Director and founder of the Environmental Policy and Innovation Center, a nonprofit effort focused on speeding up the pace of environmental progress.

COVID-19 Specific Links and Resources

See Which States and Cities Have Told Residents to Stay at Home

Coronavirus Myths versus Realities: Johns Hopkins School of Public Health Expert Insight

Wastewater Treatment Kills Most Pathogens Including COVID-19

Water, sanitation, hygiene and waste management for COVID-19

back to top