Public water systems (PWSs) are regulated by the Ohio EPA Division of Drinking and Ground Waters (Ohio EPA DDAGW). Public water systems use either a ground water source, a surface water source or a ground water under the direct influence of surface water source. In Ohio, around 4,800 public water systems serve approximately 11 million people daily. Public water systems are required to monitor their water regularly for contaminants. Currently, more than 95 percent of community water systems meet all health-based standards. When a system doesn't meet a standard, consumers are notified.
For information about individual programs, please see the pages below.
What is a Public Water System?
A public water system is defined as a system that provides water for human consumption to at least 15 service connections or serves an average of at least 25 people for at least 60 days each year. This includes water used for drinking, food preparation, bathing, showering, tooth brushing and dishwashing. Public water systems range in size from large municipalities to small churches and restaurants relying on a single well.
- Community water systems serve at least 15 service connections used by year-round residents or regularly serve at least 25 year-round residents. Examples include cities, mobile home parks and nursing homes.
- Non-transient, non-community systems serve at least 25 of the same persons over six months per year. Examples include schools, hospitals and factories.
- Transient non-community systems serve at least 25 different persons over 60 days per year. Examples include campgrounds, restaurants and gas stations. In addition, drinking water systems associated with agricultural migrant labor camps, as defined by the Ohio Department of Agriculture, are regulated even though they may not meet the minimum number of people or service connections.
Private water systems are regulated by the Ohio Department of Health. Private water systems are households and small businesses that serve fewer than 25 people per day 60 days out of the year, and are thus not public water systems (e.g., small bed and breakfasts, small day cares and small churches).
Understanding Your Drinking Water
In a typical community public water system, water is transported under pressure through a distribution network of buried pipes. Smaller pipes, called house service lines, are attached to the main water lines to bring water from the distribution network to your house.
In many community water systems, water pressure is provided by pumping water up into storage tanks that store water at higher elevations than the houses they serve. The force of gravity then "pushes" the water into your home when you turn on your tap.
Some water suppliers use treatment processes if it's necessary to remove contaminants from the drinking water. The most commonly used processes include filtration, flocculation, sedimentation and disinfection. If you want to know what types of treatment are used for your water supply, contact your local water supplier or public works department.
The Multiple Barrier Approach to Protecting Public Health
U.S. EPA and Ohio EPA use a multiple barrier approach to defend against waterborne pathogens and chemical contaminants in drinking water. Protection against contaminants occurs at each step from source to tap, beginning in the watershed or aquifer recharge area, continuing at the treatment facility and extending through the distribution system.
Source Water Assessment and Protection
Selection of the best source of water available is an important step in protecting against contamination. For surface water sources, this means locating and constructing water intakes to ensure little or no contamination. For ground water sources, this means constructing wells in appropriate locations, at appropriate depths and with approved construction methods (e.g., casing and grouting).
Source Water Assessment and Protection helps public waters systems understand where the drinking water comes from, how contaminants can get into the water supply and how to protect the water from contamination at the source. Ohio EPA completes source water assessments for every public water system. Each assessment includes:
- Delineating (or mapping) the source water assessment area;
- Conducting an inventory of potential sources of contamination in the delineated area;
- Determining the susceptibility of the water supply to those contamination sources; and
- Releasing the results of the determinations to the public.
The results of the assessment can be used to organize, develop and implement a source water protection plan.
System Design and Operation
Plan approval ensures that the system is well-engineered and constructed to reliably protect finished water from contamination. The type of treatment required depends on the physical, microbiological and chemical characteristics and the types of contaminants present in the source water. Also, storage facilities and distribution systems must have full circulation and avoid stagnant water conditions that might facilitate contamination.
Sanitary surveys are routine inspections of public water systems to ensure proper construction and operation. The purpose of the sanitary survey is to evaluate and document the capabilities of a water system’s sources, treatment, storage, distribution network, operation and maintenance and overall management to continually provide safe drinking water and to identify any deficiencies that might adversely impact a public water system’s ability to meet applicable regulations and provide a safe reliable water supply.
Competent operating personnel are vitally important to the safety of drinking water. Ohio EPA's Operator Certification rules require that certain public water systems have a certified operator that is qualified to operate the system. To become a certified operator, a person must meet educational and experience requirements, pass an exam and maintain their certification through continuing education (contact hours).
Action level: The concentration of lead or copper in water that may trigger requirements for corrosion control, source water treatment, lead service line replacement and public education. Compliance with an action level is based on multiple samples.
Human consumption: The ingestion or absorption of water or water vapor as the result of drinking, cooking, dishwashing, hand washing, bathing, showering or oral hygiene.
Maximum contaminant level (MCL): The maximum allowable level of a contaminant in public drinking water. Most often, compliance with an MCL is based on an average of multiple samples.
Maximum residual disinfectant level (MRDL): The maximum allowable level of disinfectant in public drinking water. Most often, compliance with an MRDL is based on an average of multiple samples.
Milligrams per liter (mg/L): Milligrams of contaminant per liter of drinking water.
Public water system (PWS): A system that provides water for human consumption to an average of at least 25 individuals daily at least 60 days out of the year, or has at least 15 service connections. This includes water used for drinking, food preparation, bathing, showering, tooth-brushing and dishwashing.
Community PWS: Serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents. Examples include cities, mobile home parks and nursing homes.
Non-transient, non-community PWS: Regularly serves at least 25 of the same persons over six months per year. Examples include schools and businesses.
Transient, non-community PWS: Regularly serves at least 25 different persons over 60 days per year. Examples include restaurants and gas stations.
Public water system identification number (PWSID): A unique identifier for each public water system.
Secondary maximum contaminant level (SMCL): The advisable maximum allowable level of a contaminant in public drinking water.
Treatment technique: A method for treating water to achieve acceptable levels of contaminants in lieu of establishing a maximum contaminant level.
See Ohio Administrative Code (OAC) 3745-81-01 for additional definitions.
Additional Resources for Public Water Suppliers
Rules, Policies, Procedures and Guidance
- Ohio Administrative Code Rules
- Public Water System Policy and Guidance Documents
- Water Quality Policies and Guidance
Engineering and Plan Approval
Please see the Engineering webpage for the most current versions of these documents.
Information to Assist Small Public Water Systems
- Seasonal Non-community Public Water Systems Start-up and Shut-down Checklist
- Preparing for a Sanitary Survey
- Total Coliform Bacteria Monitoring Guidance
- Please contact your Division of Drinking and Grounds Waters District Office to obtain a sample siting plan for your facility.
- Various paper forms can be found on the eDWR web page.
- Learn How to Become a Certified Water or Wastewater Operator
- Fact Sheet on Record-keeping for Operators and Owners and Certified Laboratories
- License to Operate Fees
- Emergency Preparedness and Security at Public Water Systems
- Presents resources for improving system security and preparing for emergencies.
- The "Drinking Water Supply Emergency Plan, Volume II: Public Water Systems" document discusses contingency planning. Please click on the website here and select the "Resources" tab to find the Drinking Water Supply Emergency Plan, Volume II: Public Water Systems.
- Contingency plan template
- White papers developed in conjunction with AWWA Ohio Section Technology Committee
- Checklist for Review and Optimization of Treatment for Protection Against Waterborne Disease
- Ohio's Public Water System 2021 Annual Compliance Report
Announcement for 2015: Funding is Available Through the Fluoridation Assistance Program
This program is available through the Ohio Department of Health and provides limited funds to reimburse communities for the start-up and maintenance of community water fluoridation. Water systems interested in applying for funding through the Fluoridation Assistance Program can access the program guidelines and application materials or visit the Ohio Department of Health website for more information.
- CDC Engineering and Operations
- Award Programs: