How to Diagnose Drainage Problems On Your Property

A lingering puddle on your lawn might look like a single, simple issue, but it is often a symptom of several intersecting drainage problems. Guessing at the cause can be a costly mistake; installing a single fix like a French drain won’t solve it if the real issue is your roof’s runoff volume or your neighbor’s elevation. This guide walks you through the exact steps to diagnose your property, from tracking where the water originates to testing what your soil does with it once it lands. By the end, you will know how to run a simple soil percolation test and have the concrete data necessary to help a professional build a permanent, effective solution for your property.

• Step 1: Compare Your Lot to Neighboring Properties
• Step 2: Assess Roof Runoff and Downspout Drainage
• Step 3: Observe Surface Water During and After a Storm
• Step 4: Check the Grade Around Your Foundation
• Step 5: Examine the Soil Beneath Your Topsoil
• Step 6: Run a Soil Percolation Test
• Step 7: Interpret Your Percolation Rate
• Step 8: Combine Your Findings to Choose the Right Fix
• Next Steps: When to Call a Professional Drainage Contractor

Before looking at your soil, stand at the property line and compare elevations. Our very first question on a wet-lawn call is how the lot sits relative to the property next door. If a neighbor’s home sits above yours, water naturally runs down onto your lot by gravity before your soil even has a chance to react.

Walk each side of your house and the back property line to note which direction the ground falls. If it drops toward you, that side is delivering water. However, you do not simply have to live with this runoff. In these situations, we routinely work with neighboring homeowners as a group, developing and executing comprehensive solutions for both properties under separate contracts.

The second major factor is how much roof drains directly onto the lot. Classic ranch homes carry extensive roof lines with limited gutters, meaning that surface area is a massive contributor to ground runoff. A long, low roof sheds a high volume of water, and with few gutters to catch it, that water lands in a concentrated line rather than spreading evenly across the property.

Walk around the house and count your downspouts, noting exactly where each one discharges. A downspout emptying just two feet from the foundation puts an entire roof’s worth of water into one small patch of soil. Also, note any stretches of roof with no gutter at all; the drip line under those runs is almost always where the grass thins out and the ground stays soft.

Two separate observations matter here, and they tell you different things. First, watch where water arrives and which way it travels during the rain. Then, come back the next day and see where it is still standing.

• Water that drains within a few hours: This is a surface routing problem. The water is arriving faster than the ground can pass it along, which tells you about slopes, roof volume, and neighbor runoff rather than a soil failure. This could just be the reality in the heaviest of rains. There might not be an issue so long as the water doesn’t stay for more than a few hours.
• Water still sitting a day later: This is the ground actively refusing to take the water. We see our heaviest wet-property calls between March and November, making the summer growing season the best time to catch your property’s true drainage pattern in the act.

Trace the arrival points as well as the pooling points. Downspout outlets, patios and walkways are the places runoff collects and needs capturing, which makes them the first places to look when you are working out where a puddle’s water came from. If water is running straight off of your roof, there may be an issue with the eavestroughs, or more downspouts may be needed.

Stand at each exterior wall and look at which way the soil falls in the first few feet out from the foundation. Iowa’s adopted residential code sets a specific state-wide standard for how the grade must fall away from a foundation.

What you are primarily looking for is direction. Soil that falls back toward the wall or sits dead flat sends roof and surface water directly toward your home and can end up in the basement.

Our job as landscapers is to guide water away from the house. If water is already inside your home or the basement structure itself is compromised, you need to call a dedicated basement repair contractor. We work on the outdoors above; they work on the structures below.

Take a spade to your wettest spot and dig a small hole. Across the Des Moines metro suburbs, heavy clay is a widespread problem. This is largely because developers sell off the rich black dirt when a subdivision is built, leaving homeowners with roughly six inches of good topsoil sitting over a thick layer of poor, heavily compacted material.

That lower layer governs how your lawn drains. Clay’s small particle size means that it can become very dense and compacted. This means fewer routes for water to travel, forcing it to move slowly and pool on the surface.

A percolation test (or perc test) measures exactly how fast water moves down through your soil. Here is a simple procedure you can run with standard hand tools:

1. Dig the hole: Dig a hole 12 to 18 inches deep and 4 to 12 inches wide in the soggy area you want to test.
2. Saturate the ground: Fill the hole with water and let it drain away completely. Do not skip this step. Dry soil absorbs water quickly and will give you a falsely optimistic reading. You need to know how the ground behaves when it is already wet from a storm.
3. Refill and measure: Fill the hole again and measure the total water depth with a ruler.
4. Wait and measure again: Wait exactly 15 minutes, then measure the water depth again to see how many inches it dropped.
5. Calculate your hourly rate: Multiply the drop by four (since 15 minutes is a quarter of an hour) to get your hourly drainage rate.

Tip: Run this test in a few different spots, including a normal, dry part of the lawn, to see if the whole lot shares the same poor soil or if the problem is isolated.

Soil drainage can be sorted into three main categories based on the hourly rate you determined in the previous step:

• Under 1 inch per hour (Poor Drainage): The soil itself cannot take water fast enough. Any water that lands here has nowhere to go. This is a structural soil problem, regardless of what your surface slopes are doing.
• 1 to 3 inches per hour (Normal Drainage): This is the ideal range. Your soil is behaving normally, which means your lingering puddle is likely caused by excess water volume arriving from somewhere else (like a roof or neighbor) rather than failing soil.
• Over 4 inches per hour (Very Well Drained): If a lawn with this reading still holds water, the sheer volume of arriving water is massive and needs to be intercepted.

While this test measures how quickly water moves through the ground, it does not explain why. Read our blog for advice on how to tell whether your lawn’s soil is compacted.

A slow percolation number under a puddle that lingers for days points directly to the soil. The fixes here involve giving that trapped groundwater a dedicated path out, like a French drain. Conversely, a normal soil number under a puddle that flashes and fills fast during a storm points to volume and routing. The fixes there involve capturing surface water via catch basins, swales, and regrading.

This is exactly why walking the lot and counting downspouts comes before digging. A lawn sitting below a neighbor’s property can have perfectly healthy soil and still hold water simply because it is receiving more runoff than any natural ground could handle.

The expensive mistake in drainage work is buying a fix before knowing which of these is true. Grading, catch basins, French drains and soil amendment all cost real money and all solve different problems.

A homeowner can easily handle the observations and the percolation test. However, the actual fix usually involves heavy excavation, typically digging to a working depth of 6 to 12 inches to lay pipe, holding a steady slope over long distances, and navigating local municipality rules to find a legal discharge point. A wrong guess on that final step will just send the water right back into your foundation or into your neighbor’s lawn.

When it is time to move dirt, hand your findings over to a professional. Brilliant Borders Landscaping designs and builds custom grading, catch basins, and French drains across Central Iowa. Our experts are NDS Certified Contractors, meaning we are credentialed to design, specify, and install residential stormwater management systems to official manufacturer engineering standards. We also handle the local municipal hurdles—like navigating approvals if we need to core drill into city drainage—and can help you leverage stormwater grants available in the Des Moines area.

If you are tired of dealing with a swampy lawn, request a quote to schedule a site visit and let us build a permanent solution for your property.