Groundwater Levels: How to Measure and Interpret Them
Every well owner eventually asks the same question: is my water level normal, or should I be worried? The answer lives in your groundwater level, and specifically in how it moves over time. Understanding groundwater level, both what’s happening in your own well and how your local aquifer compares to the wider region, turns a vague worry into something you can actually track and act on. This guide covers what drives groundwater levels, how to measure water level in a drilled well accurately, and how to read the national SGU data, including the groundwater depth map, that puts your well in context.
What Is a Groundwater Level and Why Does It Change?
A groundwater level is simply the depth below the surface at which the ground is saturated with water. That depth isn’t fixed. Weather, season, and how much water people draw from the aquifer beneath it drive that constant rise and fall.
How the Aquifer Stores and Releases Water
Think of an aquifer as a natural underground reservoir made of porous rock, sand, or gravel that holds water in the spaces between particles. Rain and snowmelt recharge it from above, while wells, springs, and natural drainage draw water out. When recharge outpaces withdrawal, the groundwater level rises. When withdrawal outpaces recharge, it falls. Your well simply taps into whatever level that balance currently produces.
Seasonal Patterns: What Is Normal in Sweden?
In most of Sweden, groundwater typically peaks in spring, driven by snowmelt and spring rain, then gradually declines through summer as plants and evaporation pull moisture from the soil before it can recharge the aquifer. This is exactly the pattern behind a typical well water level summer dip, and levels usually bottom out in late summer or early autumn, then begin recovering once autumn rains return and plant water demand drops. A well that follows this predictable rhythm is behaving normally, even if the summer dip feels uncomfortably low.
Long-Term Trends vs. Short-Term Fluctuations
Short-term fluctuations track the seasons and recent weather. Long-term trends track something bigger: whether your region’s aquifer is holding steady, recovering, or gradually depleting across multiple years. A single dry summer rarely tells you much on its own. A pattern of groundwater level dropping 2025 into 2026, without full recovery between years, and without the well water level gauge ever climbing back to baseline, is the signal that deserves real attention.
How to Measure the Water Level in Your Well
Knowing the regional picture matters, but your own well’s number is what actually protects your water supply.
Static Level vs. Dynamic Level: The Difference That Matters
The static water level in the well is the depth to water when the pump has been off long enough for the well to settle. The dynamic level is the depth while the pump actively runs. A well with a small, stable gap between the two is working comfortably. A gap that grows over time signals the well is having to work harder to deliver the same amount of water.
Manual Measurement: Tools and Method
To measure the water level in a drilled well manually, lower a weighted tape or marked line down the casing until it touches water, then read the depth directly off the tape. Take the reading with the pump off whenever possible, and always measure at roughly the same time of day for consistency. One caution worth repeating: in a drilled well with an installed pump, a weighted line can catch on the pump cable or drop pipe, so lower it carefully and never force it if it snags.
Continuous Electronic Measurement: How It Works
A submersible pressure sensor placed in the well measures continuously and converts pressure readings into a precise water level automatically, letting you monitor the well automatically without needing to lower anything by hand. See your well’s groundwater level in real time. Aqvify measures and alerts automatically, sending a notification the moment your level crosses a threshold you’ve set, rather than waiting for you to happen to check at the right time.
How to Interpret What You Measure
A single number tells you very little. A pattern of numbers tells you almost everything.
Building a Baseline for Your Own Well
Every well behaves differently based on its depth and the aquifer it draws from, so the most useful reference point isn’t a regional average, it’s your own well’s history. Measure consistently for a full year if you can, noting the highs, lows, and how quickly the level responds to rain or dry spells. That baseline becomes the yardstick every future reading gets compared against.
Warning Thresholds: When to Act
Set a warning threshold well above your pump’s actual cutoff point, giving yourself real lead time to act rather than reacting only once the pump starts struggling. A private well drought checklist built around clear thresholds turns a vague sense of worry into a specific, actionable trigger.
Comparing Your Well to the Regional Average Using SGU Data
SGU current groundwater levels data lets you check whether your own well’s behavior matches what’s happening across your region, or whether your situation is unusual. If SGU reports regional levels as normal but your well is dropping fast, the cause is more likely local, perhaps increased usage or a well-specific issue, rather than a broad drought effect.
Using the SGU Groundwater Map: A Practical Guide
Sweden’s national groundwater monitoring network gives every well owner a free, authoritative reference point.
How to Find the Nearest Monitoring Station
The SGU groundwater map plots monitoring stations across the country, and finding the one nearest your property gives you the most relevant regional comparison. Stations in similar geology and rainfall patterns to your own area provide a far more useful benchmark than a station hundreds of kilometers away.
Understanding the Colour Scale and What It Means for Your Area
The map’s colour scale typically ranges from much below normal through normal to much above normal, based on historical records for that specific station. Learning how to read groundwater map colours is a skill worth building: check the scale regularly through spring and summer, since a station moving from normal toward much below normal is an early regional signal worth pairing with your own well’s readings.
From Measuring to Acting: What to Do with the Data
Data only has value if it changes what you do. A groundwater level trending down, whether from your own sensor readings or the SGU map, should prompt a few concrete responses: reducing non-essential water use, checking your tank reserve, and reviewing your well’s mechanical condition before things get worse. Automatic well monitoring setups exist specifically so this response happens on your terms, with plenty of warning, rather than as a scramble after the tap already runs dry. For unexplained drops that don’t match seasonal or regional patterns, it’s also worth checking for leaks in your well and tank system rather than assuming drought is the only possible cause.
FAQ
What is considered a normal groundwater level in Sweden?
Normal varies by region and season, typically peaking in spring and dipping in late summer. The most reliable way to judge “normal” for your area is comparing current SGU station data against that station’s own historical range.
How do I measure the water level in my own well?
Lower a weighted tape or line down the well casing until it touches water and read the depth directly, or install a continuous electronic sensor that measures and logs the level automatically.
Why does groundwater level drop in summer even without a drought?
Summer combines higher plant and evaporation water use with typically lower rainfall, so aquifer recharge slows just as natural water loss increases. This produces a predictable seasonal dip even in a normal year.
How can I compare my well to the wider region?
Use the SGU groundwater map to find your nearest monitoring station and check whether its readings sit in the normal, below normal, or above normal range for that location.
What’s the difference between static and dynamic water level?
You measure the static level with the pump off and the well fully settled, and the dynamic level while the pump is running. A widening gap between the two over time often signals reduced well capacity.
Can continuous monitoring replace manual measurement entirely?
For most well owners, yes. A submersible sensor provides more frequent, more accurate data than periodic manual checks, and it removes the physical risk of lowering a weighted line near pump equipment.
