A potable water system is the infrastructure that collects, treats, stores, and distributes safe drinking water to a community. From source to tap, this process involves coordinated engineering, regulatory compliance, and long-term planning to ensure reliability and public health.

Starting at the Source: Where Does Drinking Water Come From?

Every potable water system begins with a source. Some communities rely on groundwater wells or well fields. Others draw from rivers, lakes, or reservoirs. Some purchase treated water from regional providers, while others operate blended systems that combine multiple sources to meet demand.

Each water source type presents distinct treatment requirements and operational considerations:

• Groundwater may require treatment for iron, manganese, hardness, nitrates, or emerging contaminants and disinfection prior to distribution.
• Surface water may need more extensive filtration, disinfection, and seasonal water quality management.
• Purchased water can reduce treatment responsibilities but may create dependency on another provider’s capacity, rates, and infrastructure.

Communities also need to evaluate how their water sources will perform over time. Population growth, drought, seasonal demand, industrial use, and changing environmental conditions can all affect supply. A source that meets today’s needs may not provide the same reliability years from now.

Treating Water for Safe Use

Once raw water is collected, it must be treated to meet drinking water standards and community expectations for taste, odor, clarity, and reliability.

Common treatment processes include:

• Screening
• Aeration
• Filtration
• Softening
• Disinfection
• Membrane treatment
• Chemical feed systems
• Corrosion control
• Fluoridation
• Removal of iron, manganese, nitrates, or other contaminants

In some communities, treatment improvements may involve modernizing an existing facility. In others, they may require a new plant, a new source, or update to technology to treat new pollutants of concern.

Emerging Contaminants: The PFAS Challenge

Emerging contaminants are also changing treatment decisions. Per- and polyfluoroalkyl substances, commonly known as PFAS or “forever chemicals,” are synthetic compounds that resist natural breakdown and can accumulate in groundwater, surface water, soil, and living organisms. With the U.S. Environmental Protection Agency’s 2024 drinking water limits for several PFAS compounds, many communities are reevaluating source water quality and existing treatment systems.

Conventional treatment methods are often not enough to remove PFAS effectively. Communities may need to consider granular activated carbon, ion exchange resins, reverse osmosis, or other advanced treatment systems. Engineers also use hydrogeologic modeling to evaluate how PFAS moves through groundwater, helping communities make informed decisions about source protection and treatment planning.

Why Water Storage is Important

Water storage is a critical component of a potable water system. Elevated tanks, ground storage tanks, reservoirs, and clearwells help balance supply and demand while maintaining system pressure and operational flexibility.

Because water use varies throughout the day, storage allows systems to meet peak demands from daily household activity, irrigation, industrial use, and fire response without overburdening treatment and pumping facilities. Stored water also supports system resilience during maintenance, power outages, or emergencies.

As communities grow, storage planning helps determine when additional capacity, rehabilitation, or new infrastructure is needed. Aging tanks also require inspection, maintenance, coatings, and targeted improvements to extend service life and protect water quality. Proper sizing and configuration matter: too little storage can limit growth and fire protection, while poorly configured storage can increase water age and reduce disinfectant residuals.

Moving Water Through the Community

After treatment and storage, potable water is delivered through a distribution system serving residential, commercial, institutional, and industrial users.

These systems must provide adequate pressure and reliable flow while maintaining water quality throughout the network. Thoughtful design, supported by appropriate pipe sizing, system looping, and pressure control, helps improve reliability and minimize service disruptions.

Hydraulic modeling is a key tool in this process, allowing communities to evaluate system performance, identify pressure or capacity concerns, and plan for future demand. When paired with system data and monitoring tools, modeling provides valuable insight into operational conditions and helps guide capital improvements.

In many communities, distribution system upgrades occur incrementally. Improvements such as main replacement or targeted system upgrades are often coordinated with other infrastructure or development projects to reduce disruption and maximize available funding.

Addressing Aging Infrastructure

Many communities rely on potable water infrastructure that has been in service for decades, creating significant challenges as the industry enters what the American Water Works Association has described as a critical “Replacement Era.” Across the U.S. and Canada, water systems experience approximately 260,000 water main breaks each year, with annual repair costs estimated at $2.6 billion. In North America, that equates to roughly one water main break every two minutes; while aging and leaking pipes contribute to the loss of up to 6 billion gallons of treated drinking water every day. These losses waste not only water, but also the chemicals, energy, and labor required to treat and deliver it. (Source: ASCE)

These challenges often develop gradually. Occasional water main breaks become recurring problems, water loss increases, and system components grow more difficult to maintain. At the same time, approximately one-third of water mains are now more than 50 years old, and nearly 20 percent of water pipes have surpassed their useful design life but remain in operation. (Source: 2025 Infrastructure Report Card.) Storage and treatment facilities may also require rehabilitation, development pressures can expose capacity constraints, and evolving regulations may necessitate new processes or monitoring.

A proactive approach helps shift the focus from reactive repairs to strategic investment. Tools such as condition assessments and hydraulic modeling provide a clearer understanding of system needs and help prioritize improvements over time. Advancements in smart water technology are making this work more accessible, enabling utilities to detect leaks, monitor system performance, and identify issues earlier, before they escalate into failures or service disruptions.

This type of planning is especially critical when funding is constrained. With limited resources, communities must focus on investments that deliver the greatest long-term value.

Planning for Growth and Resilience

Potable water planning is not only about maintaining today’s system. It is also about preparing for tomorrow’s demand.

Drought, extreme weather, changing groundwater conditions, flooding, power interruptions, and source-water quality concerns can all affect potable water reliability. Demand is also evolving in unexpected ways; the rapid expansion of AI data centers, for example, can create intense, localized water demands that stress municipal supply and wastewater systems in ways that traditional planning models did not anticipate.

Communities may also need to consider alternative or supplemental sources, including reclaimed water, potable reuse, or desalination in regions where traditional supplies are constrained. These approaches are increasingly part of broader water supply conversations as communities look for ways to improve long-term reliability, diversify sources, and reduce pressure on traditional groundwater and surface water supplies.

There are three primary approaches, each representing a different level of treatment and integration into the drinking water supply:

• Reclaimed water is highly treated municipal wastewater repurposed for non-drinking uses such as irrigation, industrial cooling, or other applications. Every gallon used for these purposes preserves a gallon of drinking water supply, helping to protect aquifer levels and reduce strain on treatment facilities. In communities where dual-plumbing infrastructure is in place, reclaimed water travels through dedicated distribution networks, commonly identified by purple pipe, entirely separate from the potable system.
• Indirect potable reuse takes purification further, introducing treated water into an environmental buffer such as a groundwater aquifer or surface reservoir, where it blends with natural water before being extracted and treated again for drinking. This environmental step provides an additional layer of treatment and public confidence before the water re-enters the supply.
• Direct potable reuse introduces highly purified water into the distribution system or raw water supply without that environmental buffer step. Both systems rely on a multi-stage purification process that typically includes microfiltration or ultrafiltration, reverse osmosis to remove dissolved contaminants, viruses, and pharmaceuticals, and an advanced oxidation process using ultraviolet light or ozone to address any remaining trace compounds. These systems are tightly monitored and meet or exceed federal and state drinking water standards.

Beyond Traditional Supply: Reuse and Desalination

Desalination offers another option in coastal regions or areas with brackish groundwater. Globally, there are roughly 22,000 operational desalination plants across 177 countries, generating an estimated 95 million cubic meters of fresh water per day and serving more than 300 million people daily. In the United States, more than 400 municipal desalination plants operate in states such as Arizona, California, Florida, and Texas, reflecting the growing role desalination can play where traditional water supplies are limited or vulnerable. (Source: IDRA)

There are two primary desalination methods:

• Membrane-based systems (reverse osmosis) are the most widely used approach globally, forcing source water through semi-permeable membranes that remove salts, minerals, and other dissolved substances—rejecting more than 99 percent of contaminants in the process. This method is highly adaptable and is used for both seawater and brackish groundwater sources.
• Thermal-based systems (distillation) heat saltwater to produce steam, leaving salts and minerals behind, then capture and condense that steam into fresh water. This approach is more common in regions with abundant, low-cost energy, such as parts of the Middle East, where it has been used on a large scale for decades.

Both approaches can provide a supply source that is largely independent of rainfall and surface water conditions, an important consideration as climate variability increases pressure on traditional sources.

Using Data to Make Better Decisions

Modern potable water planning is increasingly data-driven, giving communities better tools to help them understand system performance, identify vulnerabilities, and prioritize investments.

Hydraulic modeling, GIS mapping, and asset data work together to provide a clearer picture of system conditions: how water moves through the network, where infrastructure is located, and how it has performed over time. These insights help quantify issues such as water loss, track demand patterns, and support more informed planning and operations.

Communities are also expanding their use of smart water technologies to build on these capabilities. Tools allow utilities to monitor pressure, flow, and water quality in real time, identify anomalies earlier, and anticipate potential failures before they disrupt service.

Together, these capabilities improve visibility and support stronger decision-making. They also enhance funding applications by clearly documenting system needs, project benefits, and long-term value.

While data plays a critical role, it does not replace engineering judgment or local knowledge. Instead, it strengthens decision-making by providing a more reliable foundation for maintenance planning, capital improvements, system upgrades, and future growth.

Supporting Affordability and Long-Term Value

Potable water projects are not only technical projects; they are community investments funded by ratepayers, taxpayers, grants, loans, and public budgets. That is why affordability must be considered alongside performance. Communities need solutions that meet regulatory requirements and service goals without creating unnecessary financial strain.

Cost considerations can vary significantly depending on the raw water source, treatment methods, and condition of local infrastructure. In the United States, producing potable water typically costs an average of $1.50 to $3.00 per 1,000 gallons for treatment and distribution. Groundwater from wells is often less costly to produce, generally ranging from $0.10 to $0.50 per 1,000 gallons, while surface water from lakes or rivers may range from $0.50 to $1.50 per 1,000 gallons. More complex sources, such as seawater desalination, can cost $3.00 to $10.00 or more per 1,000 gallons, reflecting the additional treatment, energy, and infrastructure demands associated with those systems. (Source: Pacific Northwest National Laboratory)

Pilot studies can play an important role in managing these decisions. Testing treatment approaches on a smaller scale before full implementation can help communities better understand process performance, operational requirements, and cost considerations before committing to major capital improvements.

When communities take a long-term view, potable water investments can do more than solve immediate problems. They can reduce emergency repairs, improve reliability, support economic development, protect public health, and provide lasting value for residents and businesses.

Protecting a Resource Communities Depend On

Potable water projects are long-term commitments. The decisions made in a planning study today will shape how a community’s water system performs for the next 20 to 50 years. Communities should look for a partner with:

• Depth across the full project lifecycle: from system planning and hydraulic modeling through treatment design, construction administration, and SCADA integration.
• Funding knowledge: many potable water projects qualify for State Revolving Funds, ARPA, HMGP, BRIC, EDA grants, and other programs. A firm that understands the funding landscape can significantly reduce the burden on local ratepayers.
• Regulatory fluency: from EPA primary drinking water standards to FEMA grant compliance, the regulatory environment for water projects is layered and complex.

HR Green brings all of these capabilities to every potable water engagement, from a small community building its first distribution system from the ground up to a major metropolitan treatment plant serving tens of thousands of residents. The goal is always the same: water that is safe, reliable, and trusted by the people who depend on it every day.

Ready to strengthen your potable water system? Connect with HR Green to start planning improvements that support safe, reliable water from source to tap.