Independent Tap Water Study: Microplastics and EPA Verification Across Ten U.S. Cities

We were very excited to see this opportunity to conduct an independent water quality study. Reliable access to clean drinking water is so fundamental for public health, yet many important concerns are not sufficiently addressed. Traditional academic and government institutions struggle to integrate emerging research quickly. This project represents a perfect opportunity for DeSci to step in, where independent teams can generate transparent, open-access data to complement official reports.

1. Overview

This study aims to provide an independent assessment of tap water quality in ten diverse U.S. cities, with a primary focus on microplastics as a key emerging contaminant. In addition, the study will independently verify regulated EPA parameters (nitrates, fluoride, coliform bacteria, and basic water chemistry including pH, chlorine, and hardness) measured directly at consumer taps and public fountains, which can differ from utility plant-level reporting.

While water utilities must legally report data on 90 contaminants, research suggests that emerging pollutants like microplastics and real-world variability in water chemistry are under-monitored, leaving gaps in understanding what “safe” water truly means for consumers. This project will address that gap by:

Sampling 100 municipal tap water sources (10 per city) across varied water systems and climates.
Quantifying microplastic particle counts (with FTIR confirmation) and key chemical markers using field-friendly equipment.
Producing a transparent “Safe Water Scorecard” comparing cities and sharing open data.
Establishing a cheap and repeatable procedure for independent water monitoring.

Timeline:

Month 1: Finalize equipment, permits, and logistics.
Months 2–3: Two sampling trips (five cities each).
Months 4–5: Lab confirmation (microplastics) and microscopy counts.
Month 6: Data analysis, scorecard creation, and public report.

Funding & Facilities: The project will be managed by the lead investigator (PI) with one assistant, using portable testing kits, reusable field supplies, and a partner laboratory for microplastics analysis. Travel and equipment will be covered by the requested funding. This study involves environmental sampling only (municipal tap water), with no human or animal subjects, so Institutional Review Board (IRB) approval is not required.

Data Sharing: All raw counts (microplastics, bacteria, chemistry) and code for analysis will be released via an open GitHub repository and CSV format within six months of completion.

2. Introduction

Although the EPA requires testing for more than 90 regulated contaminants under the Safe Drinking Water Act [1], microplastics are not routinely monitored despite growing evidence of their presence. One recent study found an average of ~46 particles per liter in U.S. tap samples [2].

While conventional treatment removes up to ~90% of microplastics, tap water can be re-contaminated from aging plastic pipes, storage tanks, or airborne dust [3]. The World Health Organization’s 2019 assessment judged current exposure risks to be low, finding no clear evidence of human harm [4], but lab studies show nanoplastics can trigger inflammation and cell damage [3].

Likewise, basic chemistry indicators (such as chlorine residuals, turbidity, pH, and nitrates) can vary more than annual summaries suggest, impacting both safety perception and consumer trust. About 93% of Americans on community systems receive water that meets existing standards, yet a 2021 investigation by The Guardian and Consumer Reports still detected PFAS, arsenic, and lead across U.S. samples [5]. Utilities typically report averaged data from treatment plants, which can differ from the water quality experienced by consumers at the tap due to distribution system effects.

This study will perform an independent assessment of tap water in ten geographically and hydrologically diverse cities, focusing on microplastic counts and tap-level verification of key EPA-regulated parameters. These findings will be compiled into a public “Safe Water Scorecard” to provide residents and policymakers with an independent picture of water quality on underreported metrics. It will also establish a cheap and repeatable procedure for independent water monitoring.

The core research questions are:

How do microplastic concentrations differ across water systems that rely on varied sources (surface water, groundwater, recycled water)?
Are tap-level chemical and biological indicators consistent with utility-reported values?
How much variability in water quality exists within the same city?

Our hypotheses are:

H1) Cities sourcing water from surface water or recycled sources will show higher microplastic concentrations compared to groundwater-based systems.
H2) Tap-level measurements for regulated parameters (nitrates, fluoride, chlorine, pH, hardness, coliform) will differ measurably from utility-reported plant-level data in at least 30% of sites.
H3) Within-city variability will be greater than or comparable to between-city variability for at least one key water quality parameter, indicating distribution system or local source effects.

Impact Statement: Regardless of the specific outcomes, this project will deliver the first open, side-by-side dataset of microplastic and chemical indicators across ten U.S. cities and a U.S. territory. The results will help residents and policymakers understand how their local water compares, build public trust, and guide future monitoring of emerging contaminants.

3. Methods

Participants/Sample

Study Sites (10 cities): New York (NY), Chicago (IL), Los Angeles (CA), Houston (TX), Miami (FL), Phoenix (AZ), Denver (CO), San Juan (PR), Seattle (WA), Atlanta (GA)

These cities were selected for geographic diversity, variation in water sources (surface water, groundwater, recycled water, snowmelt), and environmental differences (urban density, storm-prone systems, arid regions). See Appendix for further explanations.

Sampling Points per City:

5 residential taps (volunteer homes, bypassing filters)
5 public sources (e.g. public fountain)

In total we would have 100 samples (10 per city). For these samples, we will select sources of municipal tap water supplied by public utilities (not bottled or private well water). We will exclude locations with point-of-use treatment (filters, softeners) unless sampling can bypass the treatment.

Materials and Procedures

To prepare for collection, we will conduct focus groups and individual interviews with relevant community members who work or live within proximity of the various water treatment facilities. These points of connectivity will allow us to learn more about existing concerns within the area and potentially lead us to uncovering other sources of contamination and concern as we proceed with our collection.

We will collect 1 liter per site in a pre-cleaned glass bottle to avoid plastic contamination. On site, the following equipment will be used:

Coliform bacteria tests: Commercial paddle kits (48-hour incubation)
Fluoride measurement: Hanna Instruments fluoride low-range portable photometer (HI99729)
Nitrate measurement: Hanna Instruments nitrate portable photometer (HI97728)
Hardness and chlorine: Commercial test strips (field screening)
pH measurement: OHAUS Starter pH Pen Meter

For 2–3 samples per city (prioritizing public sources and diverse distribution zones), an additional liter will be filtered for microplastics analysis. These will be delivered to the SimpleLab partner laboratory for FTIR spectroscopy to confirm and characterize plastic polymers, following standard QA/QC protocols.

Each measurement will be recorded with time, date, GPS coordinates, and water source type for traceability and replication.

Planned Analyses

All measurements will be compiled into a centralized dataset and analyzed to produce city-level comparisons and a final “Safe Water Scorecard.”

The metrics will include microplastic particle concentration (particles per liter), nitrate level (mg/L), fluoride level (mg/L), coliform presence (presence/absence in 100 mL), chlorine (ppm), hardness (ppm), and pH.

For each city, we will compute averages, visualize within-city variation, and test differences across and within cities. Statistical analyses will include:

One-way ANOVA or Kruskal–Wallis tests to compare microplastic concentrations across water source types (surface, groundwater, recycled), followed by post-hoc pairwise tests.
Levene’s test and paired t-tests (or nonparametric equivalents) to assess within-city variability between residential and public sources.
Pearson or Spearman correlations to explore associations between microplastics and chemical parameters such as chlorine and hardness.

Comparison to Public Data: In addition to analyzing our field results, we will compare our city-level scores with publicly available utility reports (e.g., annual Consumer Confidence Reports and EPA data). This comparison will help contextualize our findings by showing where our measurements align with, or diverge from, reported values for parameters like chlorine residuals, nitrates, and turbidity. For emerging contaminants such as microplastics, which are not included in standard reports, we will highlight these as novel findings to underscore the value of independent testing. Any discrepancies will be presented transparently, with potential explanations (e.g., sampling timing, different measurement standards) noted.

Ethics and Data Management

This study involves only environmental water sampling and does not include human or animal subjects, so IRB approval is not required. Permissions will be obtained for all private residences and public fountains where samples are collected, but no personal data or addresses will be recorded. All results will be anonymized at the city level and compiled into an open-access dataset. Final data, analysis code, and the city-level “Safe Water Scorecard” will be shared publicly via GitHub and a preprint on ResearchHub within six months of study completion.

4. Pilot Data (Optional)

Although no pilot sampling has been conducted for this project, the methods are based on well-established approaches used in prior water quality studies. Handheld meters for pH, chlorine, and turbidity, as well as commercial coliform paddle kits, are standard tools for municipal water testing and have been validated in previous research. For microplastics, the study will use FTIR-based analysis conducted by a partner laboratory, a method that meets current research standards for particle identification and quantification. These precedents indicate that the proposed approach is technically feasible and appropriate for producing reliable results across all target cities.

5. Budget

6. References

1) Safe Drinking Water Act (SDWA). EPA, (available at https://www.epa.gov/sdwa).

2) Mukotaka A., Kataoka T., Nihei Y. Rapid analytical method for characterization and quantification of microplastics in tap water using a Fourier-transform infrared microscope. Sci. Total Environ. 2021;790:148231. doi: 10.1016/j.scitotenv.2021.148231.

3) I. Gambino, F. Bagordo, T. Grassi, A. Panico, A. De Donno, Occurrence of microplastics in tap and bottled water: Current knowledge. International Journal of Environmental Research and Public Health. 19, 5283 (2022).

4) World Health Organization (WHO) Microplastics in Drinking-Water. WHO; Geneva, Switzerland: 2019.

5) 1. R. Felton, L. Gill, L. Kendall, We sampled tap water across the US – and found arsenic, lead and toxic Chemicals. The Guardian (2021).

6) Koelmans A.B., Nor N.H.M., Hermsen E., Kooi M., Mintenig M.S., De France J. Microplastics in freshwaters and drinking water: Critical review and assessment of data quality. Water Res. 2019;155:410–422. doi: 10.1016/j.watres.2019.02.054.

Appendix

Justification for City Choices

New York, NY – Largest U.S. metro; surface water from protected reservoirs; urban density and stormwater runoff make it a critical comparison point for microplastics and residual chlorine levels.
Chicago, IL – Lake Michigan source; heavy industrial and stormwater influences; useful for examining particulates and nitrate variability.
Los Angeles, CA – Blended imported, local, and recycled water; recycled content raises interest for microplastic and chemical residual variation.
Houston, TX – Mixed surface and groundwater; prone to flooding, which can drive coliform and particulate spikes.
Miami, FL – Groundwater (Biscayne Aquifer); potential for nitrate leaching and saltwater intrusion impacts.
Phoenix, AZ – Colorado River plus well water; very hard water; arid context allows comparison to low-organic, high-mineral systems.
Denver, CO – Mountain snowmelt source; serves as a “clean baseline” for comparison against coastal and urban systems.
San Juan, PR – Surface water from small plants; vulnerable to storm-driven turbidity and microplastic contamination; provides territorial representation.
Seattle, WA – Protected mountain reservoirs; low treatment needs but urban stormwater inputs make microplastic checks valuable.
Atlanta, GA – River-sourced water; aging infrastructure and heavy rain events can influence bacteria and chlorine variability.

About Our Team

Maia Adar is an independent scientist and the founder of Cosimo Research. She has coordinated several novel, non-institutional studies, including pioneering research on human pheromones and currently the first large, decentralized study on the efficacy of mouth taping for sleep. Her active involvement in DeSci and experience designing unconventional research projects ensures this study will be conducted efficiently, transparently, and with a focus on open science.
Gabrielle Napoli holds a Master’s in Public Health (MPH) from Columbia University, and is most recently in charge of overseeing Impact strategy, data, and evaluation for The Joe Torre Safe at Home Foundation. She has extensive experience facilitating programs focused on measuring public health outcomes, developing monitoring systems, and analyzing data to inform program policy, identify best data practice, and guide ongoing program improvements.

Independent Tap Water Study: Microplastics and EPA Verification Across Ten U.S. Cities

Independent Tap Water Study: Microplastics and EPA Verification Across Ten U.S. Cities

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Request for Proposals - Comprehensive Analysis of Water Quality in Urban U.S.

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