City water is the source most Americans assume is safe. And in the sense that it meets EPA standards and is disinfected for biological contaminants, it generally is. But “meets EPA standards” and “contains nothing you should worry about” aren’t the same thing.

• What your city adds: Chlorine or chloramine for disinfection. Fluoride in many systems. Corrosion inhibitors in some.
• What treatment creates: Disinfection byproducts (trihalomethanes and haloacetic acids) that form when chlorine reacts with organic matter. Present in virtually every chlorinated system.
• What treatment doesn’t remove: Pharmaceuticals. Microplastics. Most PFAS compounds. Emerging contaminants that haven’t been added to the regulated list yet.
• What enters between the plant and your tap: Lead from pre-1986 plumbing. Copper from corroding pipes. Sediment from aging distribution mains. Your utility tests at the plant and at a small number of sample homes. Your home is almost certainly not one of those sample locations.

If you’re on a private well, no federal agency tests your water. No state agency monitors it. No annual report arrives in your mailbox. Whatever is in the groundwater beneath your property is what comes out of your tap, and it can change over time without warning.

• What’s commonly found: Iron and manganese (the most common well water complaints). Hydrogen sulfide (the rotten egg smell). Hardness minerals. Bacteria (coliform, E. coli). Nitrates from agricultural runoff. Arsenic, radon, and uranium from naturally occurring geological deposits. Tannins from decaying organic matter. And in many areas, PFAS from industrial contamination or agricultural chemicals.
• Why it changes: New construction nearby can affect your aquifer. Agricultural practices shift seasonally. Drought concentrates contaminants. Flooding introduces surface contamination into groundwater. A well that tested clean five years ago may not test clean today.
• What most well owners don’t realize: Your well doesn’t pull from a static underground pool. Groundwater moves. Contaminants from miles away can migrate into your aquifer over years. The farm three properties over, the old gas station down the road, the septic system that’s been leaching for decades, all of these can affect your well without you seeing, tasting, or smelling any change.

This is the section we want to spend the most time on, because lake water homeowners are underserved by the water treatment industry and almost completely overlooked by the water testing industry.

Thousands of homes across the country draw water directly from a lake through a private intake pipe. Lakefront cabins, rural properties, seasonal residences, and year-round homes on lakes in every region of the country pump surface water straight into their plumbing.

Unlike well water, which is at least filtered through layers of soil and rock before reaching your pump, lake water sits in the open. It’s exposed to everything the watershed drains into it. And its quality changes constantly.

Why lake water is the most unpredictable source you can have

Lake water shifts with the seasons, the weather, the temperature, and the activity on and around the lake. A sample taken in April can look completely different from one taken in August. Heavy rain introduces a surge of runoff. Summer heat triggers algal blooms. Boat season adds fuel contamination. Winter turnover stirs up sediment from the bottom.

No other residential water source is this variable.

What’s commonly found in lake water

• Bacteria and parasites. E. coli, coliform bacteria, Giardia, and Cryptosporidium are all commonly present in surface water. Animal waste, waterfowl, septic seepage, and upstream agricultural runoff all contribute. Unlike well water, lake water has no natural filtration barrier between contamination sources and your intake.
• Algae and cyanobacteria toxins. This is the risk unique to lake water and the one that concerns us most. During warm months, many lakes experience algal blooms, including potentially toxic cyanobacteria (blue-green algae) blooms. These produce microcystins, cylindrospermopsin, and other toxins that can cause skin rashes, gastrointestinal illness, liver damage, and neurological effects.
• Pesticides, herbicides, and fertilizer runoff. Everything applied to lawns, farms, and golf courses in the watershed eventually drains into the lake. Nitrogen and phosphorus from fertilizers feed the algal blooms. Pesticides and herbicides introduce chemical contaminants that persist in the water.
• Boat fuel and marine contamination. If your lake has motorized boat traffic, hydrocarbons from fuel and oil are present in trace amounts. Marinas, dock runoff, and fuel spills introduce petroleum-based contaminants that you won’t taste or smell at low concentrations but that are present.
• Heavy metals, PFAS, and industrial contamination. Depending on the watershed, lake water may contain metals from road runoff (including road salt in winter), upstream industrial discharge, and PFAS from wastewater treatment plants and agricultural applications. Surface water is one of the primary pathways for PFAS contamination.
• Sediment, organic matter, and turbidity. Lake water is inherently more turbid than well water or city water. Suspended sediment, algae particles, decaying vegetation, and organic matter are always present. This is why lake water often has a color, taste, or smell that other sources don’t.

Why lake water needs the most comprehensive treatment

Lake water requires more treatment stages than any other residential source because it carries contaminants across biological, chemical, and physical categories simultaneously. At minimum, a lake water home needs sediment filtration, activated carbon for chemical contaminants, UV disinfection for bacteria and parasites, and reverse osmosis for safe drinking water.

This section is specifically for you

We talk to well water homeowners every day. We talk to city water homeowners every day. But lake water homeowners are the group we hear from least, and frankly, the group we want to hear from most.

If you draw your water from a lake, we want to know:

• What lake are you on? We’re genuinely building a better understanding of which lakes and regions have the most active lake water treatment needs.
• Have you ever tested your lake water? If so, what surprised you? If not, what’s stopped you?
• Have you noticed changes? Seasonal taste or color shifts? An algal bloom that changed everything? A year where the water suddenly got worse?
• What are you currently using for treatment? UV? Carbon? Sediment filter? RO? Nothing? How’s it working?
• Any unexplained symptoms? Have you experienced skin rashes, gastrointestinal issues, or other health symptoms that you’ve wondered might be connected to your water?

We ask because lake water treatment is one of the most complex and least standardized areas of residential water treatment. Every lake is different. Every intake depth and location is different. Every watershed carries different contaminants. The more we hear from lake water homeowners about what they’re experiencing, the better we can help the next one who calls.

Drop your answers in the comments. Even one sentence helps. And if you have a question about your specific lake water situation, ask it below. Our team responds to every comment.

There’s a romanticized version of spring water in most people’s minds: crystal-clear water bubbling up from deep underground, naturally filtered through ancient rock, pure and mineral-rich.

Some springs deliver exactly that. Others deliver bacteria, parasites, arsenic, radon, uranium, and agricultural runoff.

The quality depends entirely on the geology, the depth, the surrounding land use, and whether the spring is a true deep groundwater emergence or a shallow seep that’s essentially surface water with a scenic entry point.

• What’s commonly found: The same contaminants as well water (because springs are groundwater reaching the surface), plus biological contamination risks if the spring is shallow or poorly protected. Coliform bacteria are frequently detected in untested springs. Nitrates from agricultural areas. Naturally occurring minerals that may be beneficial or harmful depending on concentration.
• The risk: People who collect spring water for drinking often do so because they believe it’s inherently pure. That belief is the risk. Without testing, you don’t know whether your spring contains elevated arsenic, radon, bacteria, or other contaminants that are colorless, odorless, and tasteless.

Rainwater harvesting is increasingly common, particularly in drought-prone regions and off-grid homes. Many homeowners assume rainwater is pure because it comes from the sky. It isn’t.

• What’s commonly found: Atmospheric pollutants absorbed during rainfall (particulate matter, industrial emissions, vehicle exhaust). Contaminants from collection surfaces (roof materials, gutters, bird droppings, leaf debris). Bacterial contamination from standing water in collection tanks. In areas near industrial activity, rainwater can contain elevated heavy metals.
• The risk: Collection systems rarely include treatment beyond basic sediment screening. The water sits in tanks where bacteria can colonize. And your roof introduces whatever has accumulated since the last rainfall: dust, pollen, animal waste, roofing material particles, and atmospheric deposits.

Every water source carries contaminants. The type, concentration, and combination vary by source. City water has treatment chemicals and their byproducts. Well water has geological and agricultural contaminants. Lake water has biological, chemical, and seasonal contamination that makes it the most variable of all. Spring water and rainwater carry their own risks that the “natural” label obscures.

The treatment that’s right for one source may be completely wrong for another. A carbon filter that solves a city water chlorine problem does nothing for lake water bacteria. An iron filter that addresses well water staining does nothing for rainwater particulate contamination.

Regardless of source, the test is what tells you which treatment you actually need. Everything after it is guesswork without it.

Two tests cover every source in this guide. Pick the one that matches where your water comes from.

Both include certified lab analysis, results in 3 to 5 business days, a one-on-one call with a Certified Water Specialist who reviews every finding and builds a personalized treatment plan, and full cost credited toward your system purchase. Free shipping both ways.

Shop WaterLogix

• City water. The Bodyguard Whole House Water Filter for chlorine, chloramine, and chemical reduction at every tap. The American Made RO (from $599) for dissolved contaminants at the kitchen faucet. Softening if hardness is present.
• Well water. Custom treatment based on your test results. May include iron removal, sulfur treatment, softening, UV disinfection, carbon filtration, and/or RO. Explore well water solutions.
• Lake water. Typically the most comprehensive treatment: sediment filtration, whole-house carbon, UV disinfection for bacteria and parasites, and RO for drinking water. Your specialist designs the system around your specific lake water findings.
• Spring water and rainwater. Similar to well water treatment with added emphasis on bacterial protection. UV disinfection is almost always part of the recommendation.

This is the part where we ask for your help.

We’ve covered the most common water sources in this guide. But water is endlessly variable, and the real expertise comes from hearing what homeowners actually experience with their specific source, in their specific region, at their specific property.

So here’s what we’d like to know:

• What’s your water source? City, well, lake, spring, rainwater, or something else entirely?
• What’s it like? Does it taste good? Smell off? Leave stains? Look cloudy sometimes?
• Have you tested it? What did you find? What surprised you?
• What treatment do you have? Is it working? Is something still not right?
• If you’re on lake water specifically: Which lake? What region? What have you noticed seasonally?

Every answer helps us understand the real-world water situations homeowners are dealing with. And if you have a question about your specific situation, ask it in the comments. We respond to every one with a real answer from someone who actually knows water treatment, not a chatbot, not a canned response.

Your water story might be the one that helps the next reader recognize their own problem and take the step to test.

Talk to a Water Expert: (800) 608-8792