Houston Public Works Water Quality Report

DID YOU KNOW water quality reports, also known as “Consumer Confidence Reports (CCRs),” are annual documents that all public water systems are required to provide to you via mail and online. These reports are supposed to provide important information about the quality of the drinking water delivered over the previous year.

They can be difficult to read or understand. They are often many pages long and contain complex tables and charts. Culligan Water wants to change this and help you MAKE SENSE OF YOUR WATER.

This easy-to-read report will provide you with the following:

1) Infrastructure & Water System Overview

Houston Water (Main System TX1010013) operates one of the nation’s largest systems, serving ~2.4 million customers and producing an average of ~509 million gallons/day. The system blends surface water (≈86.5%) with groundwater (≈13.5%) from deep wells. Houston maintains 3 surface water purification plants and 39 groundwater plants across its service area and nearby community systems. Current reliability work includes leak detection and main replacements; the system’s Infrastructure Leak Index (ILI) was 5.22 in 2024, reflecting ongoing efforts to control real water loss.

2) Water Sources and Usage

Houston’s largest water treatment location supply comes from:

Belleau Woods receives treated water from the City of Humble; additional groundwater plants support systems such as Kingwood, Willow Chase, District 73, and District 82.

3) Disinfection and Water Treatment

Water is treated to meet federal and state standards using multi-stage processes (coagulation, sedimentation, filtration, and disinfection) prior to storage and delivery. The program targets microbial risks and common source-water contaminants (inorganic salts/metals, organics, pesticides/herbicides, and radionuclides). Arsenic occurs at low, compliant levels in parts of the system.

4) Minerals and Water Quality Highlights

Because much of Houston’s supply is surface water blended with deep-aquifer groundwater, tap water naturally contains dissolved minerals. Hardness varies by service area but is commonly in the moderate range for surface-water zones and higher where groundwater is prominent. Mineral content can leave film on fixtures/glassware and reduce soap efficiency—typical reasons residents explore whole-home softening and point-of-use filtration.

5) Lead & Service Line Inventory (What Houston Is Doing)

Lead typically enters water from home plumbing or service lines, not from the treatment plants. Houston is completing a Lead Service Line Inventory across its six distribution systems and offers free lead/copper testing for qualifying homes.

Lead: 4.4 ppb (90th percentile result; 90% of samples below the EPA action level of 15 ppb) — nine homes tested above 15 ppb, typically due to household plumbing materials.

Copper: 0.25 ppm (90th percentile result; 90% of samples below the EPA action level of 1.3 ppm) — only two homes tested slightly above 1.3 ppm, indicating strong corrosion control performance system-wide.

Residents can check the Interactive Inventory Map and self-report unknown materials with photos.

Houston’s drinking water consistently meets all federal and state safety standards but may still contain trace levels of naturally occurring minerals and disinfection byproducts. These substances aren’t usually dangerous but can influence taste, odor, or water hardness — especially in areas where groundwater blends with surface water. Below are a few common water quality factors observed across the Houston region.

Unregulated contaminants and treatment byproducts are monitored by Houston Public Works to help identify potential long-term effects and guide future safety standards. While results remain below EPA thresholds, these compounds — such as Haloacetic Acids (HAA5) and Total Trihalomethanes (TTHMs) — can impact taste and overall water quality perception.

Houston’s water is classified as moderately hard, averaging around 110 mg/L (≈6–7 grains per gallon). Hard water isn’t a health risk but may cause scale buildup on faucets, showerheads, and plumbing fixtures, reducing efficiency of soaps and appliances. A water softener helps protect plumbing systems and keeps fixtures looking clean.

Beyond regulated and hardness-related concerns, Houston’s water contains minerals and characteristics that can affect taste, clarity, and pH balance. These parameters don’t pose health risks but can influence plumbing performance and appliance longevity.

PFAS (per- and polyfluoroalkyl substances), commonly known as ‘Forever Chemicals,’ water contamination impacts residents in many places across the United States. Every five years, the U.S. Environmental Protection Agency (EPA) implements the Unregulated Contaminant Monitoring Rule (UCMR). The purpose of UCMR is to collect data from utilities like ours about contaminants that may be present in drinking water. The EPA uses this data to decide if specific contaminants occur at frequencies and concentrations high enough to be regulated in the future.

Trace amounts of naturally occurring or man-made substances can sometimes find their way into drinking water supplies, and not all are currently regulated by EPA. Today’s advanced analytical methods can detect contaminants at trace levels, but the presence of trace levels does not necessarily pose a safety concern. 

Five of the City of Houston’s systems are participating in the EPA’s fifth round of UCMR testing, known as UCMR5, which requires us to monitor for 30 chemical contaminants using analytical methods approved by EPA. It can be a lengthy process to set drinking water regulations, but it is important that EPA completes its thorough, scientific process to fully understand the potential health impacts, maximum contaminant levels, analytical methods, and treatment methods to provide public utilities with proven, consistent standards.  To learn more about PFAS testing in Houston, click here.