Ann Arbor Water

Did you know that the Ann Arbor Water Treatment Plant conducts ongoing research to improve the quality and reliability of your drinking water? This year, our work earned national recognition at the American Water Works Association’s Water Quality Technology Conference, where our team, led by Rebecca Lahr, the city’s Drinking Water Quality Manager, delivered five presentations—a notable achievement for a single utility. Our presence at this conference underscores Ann Arbor Water’s leadership in drinking water science and our active role in advancing best practices across the industry.

While we continue to meet all state and federal drinking water regulations, our commitment goes further. Research helps us refine our treatment processes, prepare for future challenges, and ensure that residents benefit from the latest advancements in water technology.

Current projects include:

• Evaluating our UV disinfection system to optimize performance
• Exploring new softening technologies as we plan upgrades to our historic 1930s softening basins
• Studying treatment approaches for emerging contaminants, ensuring we stay ahead of evolving water quality issues
• Improving the efficiency and reliability of our data management systems

Our research efforts bring together a strong team of Ann Arbor Water staff, University of Michigan faculty, staff, and students, along with experts from Jacobs and AECOM. We extend our thanks to all our collaborators for their partnership and contributions.

Together, we are working to ensure that Ann Arbor’s drinking water remains safe, reliable, and resilient for years to come.

You may not realize that the City of Ann Arbor already softens your drinking water, removing minerals at the treatment plant and carefully balancing what remains to protect a household’s plumbing.

Here’s the trick: When water leaves our plant, its chemistry is tuned to build a thin, protective mineral coating inside pipes. That tiny layer of scale—usually a white or tan calcium carbonate film—helps keep metals from leaching into your drinking water. We post daily data on calcium, alkalinity, pH and other measures that keep this balance just right.

So where do home water softeners come in?

Some residents choose to soften their water even further. That’s fine—but it does change the water chemistry after it enters your home. And when chemistry changes, your pipes notice.

A softener removes calcium, which is one of the key ingredients for that protective scale. Without it, the water flowing through your indoor plumbing may become more corrosive. This matters especially if you have:

• Older brass faucets (pre-2014) that may contain lead
• Copper pipes joined with lead solder

In these cases, an overly softened water supply can increase the chance of metals dissolving into your tap water.

If you choose to install a softener, follow the manufacturer’s instructions carefully and keep an eye on your plumbing for signs of corrosion. If you’re seeing white scale on faucets or in your dishwasher, that’s normal and easily removed with vinegar or a limescale cleaner.

For more information about protecting your home plumbing, visit our Lead and Copper webpage: www.a2gov.org/lcr

If you have more questions about your tap water, check out our Drinking Water FAQ to learn about:

• Tracking water use or leak alerts with AquaHawk
• What faucet aerators are—and how to clean them
• Why backflow prevention matters
• What to do if your water looks, tastes, or smells “off”
• And much more

On Dec. 10, staff responded to reports of mysterious foam along Liberty Road near Zion Church. Out of an abundance of caution, city crews placed absorbent booms to capture any possible contaminants and collected samples of the sudsy substance for testing. 

Our initial investigation identified a far less alarming—though surprisingly fascinating—culprit. The bubbles appear to be saponins, natural compounds released from the seed pods of the many honey locust trees lining the corridor. When the pods or leaves get soaked and agitated (say, after a rainstorm), they can foam up in a way that looks straight out of a car wash.

Fun fact: the Asian relative of the honey locust, Gleditsia sinensis, is sometimes called the “soap pod” tree because its bark and seeds were traditionally used as a natural cleanser. So, while it’s not exactly a new cleaning product on the market, nature seems to be creating a street based bubble bath.

Test results that came in later supported our first impression, low level surfactants from the seed pods. 

Winter can mean slippery surfaces. Therefore, residents and property owners are responsible for clearing snow/ice from adjacent sidewalks, crosswalk ramps and bus stops. 

Keeping sidewalks safe can be aided by a variety by de-icing products. Ultimately each de-icing option has benefits, limitations and drawbacks.

Salt can be the least expensive and is the most abundant material for ridding surfaces of ice. However, its effectiveness drops as walking surfaces fall below 18 degrees Fahrenheit. In addition, overuse can pollute water supplies.

The city provides city residents with up to 5 gallons of a sand/salt mixture, per visit at these locations:

• ​Veterans Memorial Park
• Gallu​p Park
• All​mendinger Park
• Buhr Park
• Burns Park
• Leslie Park ​

Residents should bring their own shovel and bucket, and load material themselves from the ​marked pile. This material is not for contractors. ​For more information, and maps to help you find the material, please visit www.a2gov.org/snow.   

There are several kinds of non-toxic materials available for purchase, which if you have pets, can be a good choice. Some solutions, like products containing calcium chloride (CaCl2), can melt snow at lower temperatures, is less harmful to plants and animals, but eats into metal and concrete. In addition, CaCl2 binds to water and can’t be separated, which has the potential to do permanent harm to the environment.

Products that contain potassium acetate can block ice from forming at very low temperatures, are noncorrosive and biodegradable, however, these products lower oxygen levels in water and can harm fish and plants in our waterways.

Various brines can help prevent ice from sticking to surfaces, alternatively using a bit of sugar in salt can lower the temperature at which it’s effective. When in doubt, the best course of action is to use as little de-icer as possible and, if feasible, use physical labor to remove ice or snow.

Winter can cause havoc on anything at your residence that carries water. Check pipes and all spigots on the outside of your home during extreme cold spells to prevent them from freezing.

Here are some winter tips to remember:

• For pipes located within cabinets, open the doors to allow warm air to circulate. If you have young children, move chemicals or cleaners so they remain out of reach.
• Insulate any outdoor spigots or pipes.
• Let your faucet drip to keep water moving through pipes.
• Set your thermostat to the same temperature day and night. A slightly higher heating bill is far less expensive than the expense of a broken pipe and possible flooding.
• If you are away from home, set your thermostat no lower than 55 degrees.
• In the long term, consider moving exposed pipes inside and adding insulation to pipes in crawl spaces and attics.

Did you know that as a resident of Michigan you’re never more than 85 miles from a Great Lake? In fact, living in Michigan means you’re never more than six miles away from a body of water! Rivers, lakes, streams, creeks, water is always right at your fingertips. Which all means it is critical we’re always thinking about ways to protect it, both for our ecosystem and for drinking.

Learn how the city is using a One Water approach to plan and protect our source waters. 

Flooding can happen quickly—and being prepared can make all the difference. Here's how the City of Ann Arbor and its residents can stay ready before, during, and after a flood:

Ann Arbor is StormReady!
The City’s Office of Emergency Management works closely with the National Weather Service to receive real-time weather alerts. These are shared with the public through:

• Everbridge A2 Emergency Alert System (don’t wait, sign up today!)
• Outdoor Warning Sirens
• Wireless Emergency Alerts (WEA) from the National Weather Service (make sure your phone hasn't opted out of these!)

Stay Aware of Rising Waters
The City monitors water levels using three U.S. Geological Survey (USGS) stream gauges. View current conditions here:

·         Stream Gauge Info

Be Ready at Home
Learn how to prepare your household for flooding with helpful tips and checklists at:

·         ready.gov/floods

Get Emergency Alerts
Sign up to receive critical weather and safety notifications directly to your phone or email:

·         A2 Emergency Alerts

Next time you walk near Barton, Argo, Geddes or Superior dams on the Huron River, take a moment to notice the debris caught in the gates—it tells a story about the human impact on the river. Much of the trash you see didn’t start there. It began on streets, sidewalks, or park trails, where it was left behind or carelessly discarded. Rain can wash that litter into storm drains, which flow directly to the river—one of our drinking water sources.

To help draw attention to this issue, the City of Ann Arbor has a display to show just how much trash accumulates and how it affects both the health of the river and dam operations. When trash gets stuck in the dam gates, city crews must physically remove it—a time-consuming and costly task. And if the trash floats past the dam, it simply becomes someone else’s problem downstream.

The good news is that everyone can help. Here’s how:

• Don’t litter. Even small items like bottle caps, straws, and food wrappers can end up in the river.
• Pick up after others. If you see trash on the ground, consider picking it up—every little bit helps.
• Secure your trash and recycling. Make sure bins are covered and materials aren’t loose, especially on windy days.
• Be a responsible paddler. If you're enjoying the river or the Argo Cascades, bring a bag for any trash and carry everything back with you.

Together, we can protect our waterways, reduce maintenance costs, and preserve the Huron River for ourselves and our neighbors. Clean streets mean a cleaner river—and cleaner water for all.

Construction is progressing steadily at the Barton Dam Right Embankment, where a major infrastructure upgrade will improve dam safety. The project focuses on resolving long-standing seepage issues by replacing the original, failed drain system with a new mineral drain. This upgraded system uses layers of sand and gravel to safely direct groundwater to a collector ditch, helping to protect the dam’s integrity.

This $13 million project (studies, design, construction) is being carried out by Michels Construction, with engineering support from NTH and Geosyntec. It is a required improvement under the Federal Energy Regulatory Commission (FERC) guidelines. Necessary permits were obtained from the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and Amtrak to ensure environmental and site access compliance.

As of July 2025, more than 20% of work has been completed. Please remember that the portage and site are closed and no public access is available. The site is an active and restricted construction zone and unauthorized entry could present a serious safety hazard.

The Michigan Department of Health and Human Services has issued its Safe Fish Guide for 2025. This information is very useful for anyone planning to fish in Michigan’s streams, rivers and lakes. The guide is broken down by region, river area and even gives information about advisories in other states bordering the Great Lakes.

Did you know that Ann Arbor Water keeps a close watch on the Huron River for harmful algal blooms (HABs) and their toxins? 

These naturally occurring blooms—caused by certain types of bacteria called cyanobacteria—can sometimes produce toxins, but rest assured: Ann Arbor’s water is safe to drink.

Our water treatment plant tests for over 200 potential contaminants and runs more than 175,000 water quality tests every year. Our Annual Water Quality Report shows only a subset of these analyses because it does not include contaminants that we do not detect. One of these classes of contaminants that was not detected this year in treated drinking water is toxins from Harmful Algal Blooms. 

We use advanced treatment methods that effectively remove toxins—without needing any changes if a bloom were to occur. We also monitor upstream activity and follow a detailed HAB response plan to stay ahead of any issues.

There are currently no federal regulations for algal toxins, but the Environmental Protection Agency (EPA) offers health guidelines—and Ann Arbor uses even more strict safety limits for all residents. The toxins we test for are consistently undetected or well below those limits.

Ann Arbor’s advisory levels for all consumers are 0.3 parts per billion (ppb) microcystins and 0.7 ppb for cylindrospermopsin. Over the past four years in the untreated source water from Barton Pond, the cyanotoxins anatoxin-a, cylindrospermopsin, and nodularin were not detected, and total microcystin concentrations were below <0.3 ppb.

The City of Ann Arbor's annual fire hydrant flushing will resumed on Monday, March 31. Annual fire hydrant flushing resumes every spring and continues weekly until all hydrants in the city are serviced. This preventative maintenance is done to remove minerals and sediment that accumulate in the water lines over the course of a year. During this work staff will also check and record water pressure to ensure the water system is functioning properly.​​

Where is flushing occurring?

• A graphical map is updated only during annual spring hydrant flushing to show which areas of the city are having their hydrants flushed.
• ​Other preventative maintenance flushing done throughout the rest of the year may not appear on this map.
• ​​You may observe nearby neighborhood fire hydrants with water coming out of the side opening.

On occasion during the hydrant-flushing process, the water in area homes may have an orange or rusty appearance. This discoloration is caused by the disruption to the iron sediment in the water pipes. The water is safe to drink, as the discolored water does not pose a health or safety risk. The discolored water can cause stains to laundry. Temporary laundry coloration caused by this sediment can be removed by using a product called “Rover."​

• If water appears discolored, run the cold water for several minutes and flush your toilets to clear your lines. 
  • Do not run the hot water, as rusty water may get into the hot water tank mixing it with the clear stored water. 
  • If you do get rusty water in your hot water heater, drain the hot water heater per the manufacturer's instructions. 
• ​The water should run clear within a few minutes, but may last until the evening when hydrant flushing stops and more people are home to move the rusty water out of the system.

If you have any questions or concerns regarding hydrant flushing, please call the city at 734.794.6320.

Tour the Ann Arbor Water Treatment Plant, learn from the experts about Ann Arbor's award-winning water and take part in hands-on activities at the Ann Arbor Water Open House Saturday, May 10, 10 a.m.–2 p.m. at 919 Sunset Road. The annual event is free and takes place in celebration of National Drinking Water Week May 4–10.

Get ready to soak in the beauty of the Huron River at the annual Huron River Day (HRD) Sunday, May 18, noon–4 p.m. at Gallup Park (3000 Fuller Road)! This free, family-friendly event is the perfect way to spend an afternoon, surrounded by nature, music and a whole lot of fun. Sponsored by DTE Foundation, this celebration (now in its 45th year) is part of what makes Ann Arbor’s green spaces and happy places so special.

Whether you're walking, driving or biking to Gallup Park, there's no shortage of ways to enjoy the day. Cyclists can take advantage of a complimentary bike valet provided by Common Cycle, making it easy to park and explore. Once you're there, you'll find plenty of hands-on activities, live animals, food trucks and exhibitors showcasing educational and eco-friendly fun! More details will be added later in April. Stay tuned by visiting the event webpage. 

The Ann Arbor Water Treatment Plant (WTP) Facility Plan began in mid-2022. Since then, the team continues to make progress on multiple project tasks. The project includes a strategic plan, an alternatives analysis study, pilot plant testing, and community engagement. For more information about this project, visit the project website.

Following are completed tasks to date as well as what items will be completed in the future.

• Strategic Planning has been completed with the city adoption of the Strategic Plan in February 2024. The Strategic Plan is available to view online.  
• A pilot plant has been constructed at the Water Treatment Plant and became operational in spring 2024. The pilot plant  is where city staff test new technologies, new equipment and treatment methods. At least 12-months of pilot testing is required in the plan. Testing will continue through summer 2025.   
• City staff continue to work closely with the State of Michigan Department of Environment, Great Lakes, and Energy (EGLE) through this process. Together, the city and EGLE have been reviewing pilot plant performance data.
• WTP Facility Plan planning efforts will continue through summer of 2026. Some of the upcoming efforts include:

1. 1. Developing a recommendation on the treatment process selection.
   2. Developing conceptual site plan layouts.
   3. Preparing conceptual construction cost estimates.

On January 28, 2025, key staff from Ann Arbor Water and their engineering consultant, OHM Advisors, came together with city retirees to discuss the city’s water system. Coined as “historians”, these retirees have a vast understanding and knowledge of the city’s water system and were able to provide additional historical context as work progresses on the Water Distribution Plan.

Topics such as pressure districts, connections, redundancy, and emergency response were discussed. Thank you to the following city retirees who shared their experience with the project team: 

• Craig Hupy, former Public Services Area Administrator
• Larry Sanford, former Assistant Water Treatment Plant Manager
• Bill Wheeler, former Public Services Area Administrator 

Adjacent to Barton Pond, Barton Nature Area, Bird Hills Nature Area and trails to and along the Huron River, construction activity continues for the Barton Dam embankment remediation project. Public access is restricted in designated areas. This includes no public on-site access to Barton Pond.  

When visiting this area, please note the posted safety restrictions, barricades and signage on site and use caution in areas that remain open, such as the parking lot, pathway and other areas west of the Huron River, as some of these open areas will be shared by construction operations and construction traffic. This project is anticipated to be completed by June 2027. The city thanks community members for their patience during this Federal Energy Regulatory Commission (FERC)-required project. 

Work continues on the update of the City’s Comprehensive Water Distribution Plan. When complete, this plan will be used to evaluate current practices, ensure preparedness for emergency situations, and ensure a sustainable and resilient water system. The results of this plan, coupled with the results of the Water Treatment Plant Facility Plan, Strategic Plan, and the Source Water Protection Plan will be used to plan,  prioritize, and budget water system improvement projects.

A key part of this work involves the updating and calibration of the City’s Hydraulic Model, which is now complete. A Hydraulic Model is a sophisticated tool that will serve as an essential asset for long-term planning, allowing the City to analyze and optimize water system operations, level of service, enhance fire protection capabilities, and respond effectively to emergency situations.

A Comprehensive Water Distribution Plan involves engagement of key stakeholders, such as the University of Michigan and surrounding communities. The project team continues to connect with these stakeholders to gather their input and understand their current and future needs. The information collected from these stakeholders will be used to assess the future system and identify any capital projects that will be needed to operate the water system efficiently.