TapTool - About the Data

We created TapTool to help Americans better understand their local water quality and take actionable steps to ensure their drinking water is safe for their home and family. TapTool is the first tool to combine local drinking water contaminant data and pollution contaminant data into one comprehensive source. It is also the first tool to compile well water data by zip code using local ground water data.

The TapTool application collects water quality data from nearly 50,000 public water systems and their surrounding water bodies (both ground and surface). All you have to do is enter your zip code and your water source (city or well water) to receive a report that details your local water quality.

Our database collects data from the following sources:

  • Environmental Protection Agency (EPA)
  • United States Geological Survey (USGS)
  • Center for Disease Control (CDC)

On this page, we will break down each section of your TapTool water quality report and help you understand why it’s important

TapTool Section Summary

Mineral Deposits and Corrosion Potential

Why it's important
Water hardness and corrosivity depend on the concentration of dissolved minerals in your water source. High mineral content water can leave deposits within your household, damage household appliances, be difficult to clean, and even impact skin and hair health. Water with low mineral content can be corrosive, increasing the likelihood that your water could contain harmful dissolved metals from the distribution system and household plumbing. Corrosive water combined with old infrastructure that contains lead piping is the leading cause of lead found in drinking water (i.e., Flint). 
How We Collected the Data
We aggregated water quality data from the USGS using public water utility information from the EPA’s Safe Water Drinking Information System (SDWIS). The data presented in this section is from the public water system’s local source waters and provides a good representation of the water you can expect at the tap.
Why you should trust it

Understanding hard water and its potential impacts can be confusing. Many water softener providers only focus on the concentration of total hardness in your water to determine if hardness deposits are an issue. However, several factors determine whether or not hardness will deposit on surfaces within your home.

Hardness-related deposits primarily consist of calcium carbonate. The formation of calcium carbonate is dependent on several water quality parameters, you’ll find these parameters displayed within this section in the TapTool application. Your water quality report accounts for all of these parameters by using Langlier’s Saturation Index (LSI) and Ryznar’s Stability Index (RSI). These indices provide an approximate indicator of the degree of calcium carbonate saturation in water.

To determine your water’s corrosivity we can also use these indices. Water that is low in pH and dissolved solids has higher corrosivity. Higher corrosivity means a greater risk of leaching harmful metals such as lead and copper into the water from the distribution system or your home. 

Water utilities typically do not treat to reduce hardness-related minerals in the water as it is expensive, and these minerals are not directly harmful to your health. Additionally, water systems can apply corrosion prevention methods, such as raising the pH or using a corrosion inhibitor; but this does not change the underlying characteristics of the water. These corrosion prevention methods are unreliable as they are subject to human error, varying source water quality, and physical distance from the treatment facility. 

You can use your TapTool result combined with observable signs of hardness and corrosion in your household to determine if further testing or filtration is necessary. 

Disinfection By-Products

Why its important

Throughout history, the primary concern with drinking water was the presence of waterborne pathogens. It wasn’t until the early 1900s that chlorination became widely used in public water systems as a disinfectant to treat these pathogens. Chlorine revolutionized water purification, reduced the incidence of waterborne diseases across the Western world, and “chlorination and filtration of drinking water has been hailed as the major public health achievement of the 20th century”.[1]

Since then, new concerns about the health effects of chlorine by-products have led to questions about the advisability of using chlorine to provide safe water. Disinfection By-Products (DBPs) are a group of EPA-regulated contaminants that form when a disinfectant, such as chlorine, reacts with natural organic substances in the water. Studies to date have shown that these products are carcinogenic over long-term exposure.

The EPA regulates two main disinfection by-products: Total Trihalomethanes (THMs) and Total Haloacetic Acids (THAAs). These two chemicals are used as indicator chemicals for all potentially harmful compounds formed by adding chlorine to water. Typical exposure to these contaminants is through oral, dermal, and inhalational contact with chlorinated water. 

In populations who take hot showers or baths, inhalation and dermal absorption in the shower account for more exposure to THMs than drinking water. Unfortunately, these disinfection by-products are a necessary evil to prevent harmful bacteria and pathogens from growing in our water. The good news is these substances can be easily removed using inexpensive point-of-use carbon filtration systems at the sink and in the shower.

How We Collected the Data
We collected disinfection by-product data from the EPA’s most recent 6-year review of public water systems and the CDC Environmental Tracking Tool. The CDC Environmental Tracking Tool is more recent data released in 2021 for public water systems. The EPA 6-year review is a program implemented by the Safe Drinking Water Act (SDWA) that requires the EPA to review national primary drinking water regulations. As part of the review, the EPA analyzed contaminant occurrence in public drinking water systems for all EPA-regulated contaminants. The EPA collected water system data from 2006-2011 and released the review in 2016. 
Why You Should Trust it

While the data from the EPA may seem “dated,” it still provides the most accurate representation of the DBP levels in your water because of the frequency of data collection over an extended period. Using a large set of data such as the one provided by the EPA is important because DBPs can vary significantly within a water system based on the following factors:

  • Your home’s physical distance from the treatment facility
  • Varying composition of source water that is affected by seasonal changes such as precipitation and drought
  • Amount of disinfection applied on a particular day which is also affected by source water and seasonal changes

The DBP levels in your report are the average of the EPA’s DBP levels in your public water distribution system.

Water systems showing higher-than-average disinfection by-products represent water systems with high concentrations of organic matter that chlorine or chloramine reacts with to form DBPs.  

The facts are, if you are on city water, DBPs are present in your drinking water. If they are not present, you should be concerned that your utility is not providing the appropriate levels of disinfection to treat pathogens. Other sources list very low concentrations of DBPs for their health guidelines, contrary to the EPA guidelines. These sources specify less than 0.15 ppb for  TTHMs and less than 0.1 ppb for THAAs. DBP levels this low could be more concerning than having high DBPs, as it could be a sign that your water does not have enough disinfectant to treat waterborne pathogens.

The best way to account for DBPs in your water is to use inexpensive, point-of-use carbon or RO filtration system to ensure you are always protected.

Lead and Copper

Why its Important

The primary cause of lead in drinking water occurs when lead plumbing materials in the distribution system or home corrode. If you live in an older home built before 1986, lead piping could be present in your home or distribution system. The most common problem within homes is brass or chrome-plated brass faucets and plumbing with lead solder.

Exposure to lead and copper may cause health problems ranging from stomach distress to brain damage. In children, lead concentrations are very dangerous and can result in physical or mental development delays. In 1991, the EPA published the Lead and Copper rule for drinking water. The rule states that lead levels must not exceed 15 ppb and copper levels should not exceed 1.3 ppm in more than 10% of customer taps sampled. If a utility violates this rule, the system must undertake several additional actions to control corrosion. Lead exceedances require the water system to inform the public about steps they should take to protect their health and may have to replace lead service lines under their control.
The EPA further states that current health guidelines suggest no safe lead level in drinking water.

The EPA’s Maximum Contaminant Level Goal (MCLG) for lead is 0 ppb to account for these health guidelines. Because of this, you should be concerned if lead is detected in any concentration in your public water system, especially if you have young children at home.

How We Collected the Data

The lead and copper data in your TapTool report comes directly from the EPA’s Safe Drinking Water Information System (SDWIS) database. Any positive results are listed in TapTool with the most recent date of the sample.  All public water systems are required to report Lead and Copper monitoring every six months unless they qualify for reduced monitoring. You can view the criteria for reduced monitoring from the EPA directly here

Why You Should Trust it

The EPA  is the most comprehensive source for lead and copper in public drinking water systems. Unfortunately, accessing and understanding this data is not straightforward. TapTool makes this data more accessible by only requiring you to enter your zip code.

The Flint water crisis raised public awareness of the potential for lead contamination in drinking water and left the public questioning if it could happen to them. If you followed the flint water crisis, you likely saw images of water that was brown coming out of residents’ taps. Many people associated this brown water with the presence of lead, as this was the most concerning contaminant found in the water. However, you cannot see, taste, or smell lead in drinking water. The only way to truly know if you have lead in your water is to test it directly from your tap. 

You also need to fully understand the characteristics of your water and the metallurgy within your household to determine if lead contamination is possible. You can use TapTool’s corrosivity section as a start to determine the corrosive tendencies of your water. Understanding corrosive tendencies, combined with a thorough inspection of the lead within your household, is key to understanding the potential for lead contamination in your water. Based on your findings, you should decide if routine testing or point-of-use filtration is necessary to protect you from lead contamination

Radioactive Substances

Why it's Important

Radioactive substances contaminate drinking water through natural elements in the earth’s crust and industrial sources. Industrial sources can either be from industries such as mining that disperse the naturally occurring radioactive elements in the earth’s crust or waste from medical facilities and nuclear power plants. Trace amounts of radioactive substances such as radium, uranium, and other alpha particles exist in small quantities in drinking water throughout the United States. Long-term exposure to these substances is known to increase the risk of cancer. Exposure to uranium can result in toxic kidney effects. Because of these health concerns, the EPA regulates these substances in drinking water through the radionuclide rule. This rule requires community water systems considered vulnerable to contamination to monitor and report for these substances routinely.

How We Collected the Data

The EPA’s six-year review is the most comprehensive source for Radionuclide data.[3] Radionuclide Data is also available in the CDC’s environmental tracking tool.[2] We used these data sources to build this section in the TapTool application. 

Why You Should Trust it

The EPA’s radionuclide rule primarily focuses on community water systems susceptible to contamination because of their proximity to natural or industrial sources. The TapTool application pulls data for Uranium, Radium, and alpha particles and compares this data to the EPA’s guidelines. The EPA’s compliance guideline allows for trace amounts in drinking water before the community water system is required to take action. However, the EPA goal shows that no level of radionuclide in water is safe. Any detectable level means that your public water system source waters are close to a natural or industrial source. Treatment of radioactive material is usually too expensive for your community water system to implement. Still, you can take matters into your own hands by installing point-of-use reverse osmosis filters on your drinking water.

Source Water Contaminant Profile

Why it's Important

The EPA provides legal limits for over 90 contaminants in drinking water. These legal limits were determined using health guidelines and the contaminant levels water systems can reasonably achieve using modern treatment technologies. The EPA also sets reporting requirements that include water-testing schedules and methods the water utility must follow to achieve compliance.

For this section, we identified 15 of the most commonly found EPA-regulated contaminants in drinking water. The contaminants we identified showed the highest pollution levels in source waters throughout the United States in EPA’s ECHO Database. Many of these contaminants are also naturally occurring. Public water system treatment technologies for these contaminants are often expensive and are ineffective at removing 100% of the contaminant. 

How We Collected the Data

We aggregated water quality data from the USGS using public water utility information from the EPA’s Safe Water Drinking Information System (SWDIS). Using the zip code associated with the public water system, we averaged local source water contaminant data that is most likely to be found in your drinking water.

Why you Should Trust it

Understanding the contaminants in your source water is critical to understanding the contaminants that could potentially end up at your tap. Many of these contaminants are difficult and expensive to treat, and inconsistent treatment will inevitably lead to contaminants reaching your tap. Routine testing at the tap is the only way to fully understand how these source water contaminants affect your drinking water. You can also check your Utilities Consumer Confidence Report (CCR) to determine the average concentration level of these contaminants in your distribution system. We suggest looking at the CCR for multiple years to understand if a particular contaminant is an issue.

If you are on well water, the source water contaminant information presented should give you an idea of what sort of contaminants you might expect in your well. Well water should be tested at a minimum once per year to confirm the water you are drinking is safe! Check out TapTool for more information on the health effects of these contaminants and how to remove them if they are present.  

Watershed Pollution Data

Why it's Important

Pollution caused by industrial waste is one of the leading sources of drinking water contamination. As water bodies shrink due to climate change and pollution increases, the concentration of these contaminants is increasing over time. Understanding these pollutants and where they are coming from is key to understanding their effect on our watershed and drinking water systems both presently and in the future.  

The pollution section focuses on pollutants discharged into your public water system’s source water that could contaminate drinking water. 

Your Water quality report will tell you the following:

  1. Pollutants discharged and quantity in lb/year (2022)
  2. Affected Watersheds
  3. Permitted polluters within the watersheds affected
  4. Potential Health effects and treatment for each contaminant
How We Collected the Data

Data for this section is from the EPA ECHO database. We focused on 75 pollutants that are regulated by the EPA’s Safe Drinking Water Act (SDWA) that are discharged in your public water systems source water or in close proximity. This section also shows major dischargers only. Major municipal dischargers include all facilities with design flows of greater than one million gallons per day and facilities with EPA/state-approved industrial pretreatment programs. Major industrial facilities are determined based on specific rating criteria developed by EPA/state.

Why You Should Trust It

Your TapTool report is an excellent source of information to understand what pollutants are being released into your drinking water source water. The data is designed to be a starting point for understanding the chemicals contaminating your source waters. If there are contaminants of particular concern in your report, it would be a good idea to check your systems Consumer Confidence Report or run additional water tests at the tap to determine if these contaminants are reaching your home.

Sources and References

  1. https://www.cdc.gov/healthywater/global/household-water-treatment/chlorination-byproducts.html#twe
  2. https://ephtracking.cdc.gov/
  3. https://www.epa.gov/dwsixyearreview/six-year-review-3-compliance-monitoring-data-2006-2011
  4. https://www.epa.gov/dwreginfo/lead-and-copper-rule
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