Dry Well Vs French Drain – Which Is Better?

To determine the better option from Dry well VS French drain, it is important to know the differences between the two. These two solutions involve different mechanisms to drain water from your house to a desired spot on the land. You can pick one of these two depending on your situation. There is also a possibility of combining these two to create an efficient water drainage system. Let’s find out more about French drains and dry wells. 

How Does a Dry Well Work?

A dry well is installed underground away from the house. It collects the water from a drainage system and disperses it below the ground. This is the best option if you cannot direct your drainage system to a storm drain or a water garden. In most regions, it is illegal to direct runoff water to municipal storm drains. So, rather than flooding your lawn, a dry well allows you to get rid of the water underground. Since it does not leave traces of water on the surface, you don’t need to worry about covering up damp spots in your yard. As the water penetrates through many layers of soil, it will be filtered eventually. 

dry well vs french drain

Dry wells cannot collect water on their own. A drainage pipe or system should direct the water to the dry well. It can get water from gutter downspouts, ditches, French drains, and any drainage system. So, you don’t need to terminate the drain above the ground as you can direct it to the dry well. This prevents flooding and erosion, which is a positive impact on the environment. Keep a safe distance of at least 12 feet between the dry well and your house.

Are Dry Wells Successful?

Dry wells are tested and trusted for years of proper function. A dry well of the correct size will get rid of even a large amount of water. These have been used successfully since ancient times. Installing a dry well may be quite tiring as it needs intensive labor unless you use a digging machine. Lining the dry wells with landscape fabric and filling them with gravel increases the effectiveness.

When selecting the location to install a dry well, choose a type of soil that absorbs water well. Sandy and loamy soils are preferable, while you should avoid heavy clay soil. It is important to percolation test before the installation of the dry well. For this, you should dig a hole and fill it with water to check the rate of water absorption. If it is clay soil, the water will remain for a long time and you should not select that location. Dry wells will also work in freezing temperatures if installed correctly.

Should You Pump a Dry Well?

You don’t need to pump or empty a dry well as it will not fill up. The holes born around the well will eliminate the water into the ground over time. The gravel added to the lining helps this process, allowing the water to filter into the soil. This water will then be added to the soil as groundwater which is totally harmless.

How Does a French Drain Work?

A French drain gathers water from a flooding area and directs it to the desired place along its slight slope. It is different from a flat solid drain since a French drain consists of a perforated pipe. Since there are holes in the drain pipe, water present in any location along the length of the pipe can be carried downhill.

A French drain can collect water over a large area and bring it down to the endpoint. So, you don’t need to worry about the water penetrating into your foundation or flooding the basement. When the excess water is transmitted through the French drain, it needs a specific termination point to prevent flooding the trench. Thus, a French drain cannot function alone as it needs a specific outlet to release the water.

Suitable Endings for a French Drain

Depending on your preference, you can direct the French drain outlet to a pond, stormwater system, water garden, or dry well. It is important to check the local building codes before you decide what to choose. It is illegal to direct your runoff water into storm drains in some regions, while some other municipalities have restrictions on dry wells. However, make sure that the French drain has an outlet to prevent flooding. Do not position the outlet to drain the water into your neighbors’ property. Such acts are illegal as you should be responsible for the water collected on your premises. A dry well will be a good option to end the French drain as it prevents making your land soggy.

what is a dry well for drainage

How to Use a Dry Well and a French Drain Together?

As you are aware, French drains and dry wells can be used together. It makes the water drainage system more effective. When the French drain collects the water and directs it to the dry well, it will then disperse the water safely underground. Follow the steps given below to install this method.

  1. The first step is to dig a drainage trench with a slope of 1–2 inches for every 10 feet.
  2. Then use landscape fabric, gravel, and perforated pipe to install a French drain in the drainage trench.
  3. Dig a dry well on the previously selected location where the drainage trench ends.
  4. Depending on the requirement, a dry well can have a diameter of 3 feet and a depth of 3 feet.
  5. Install the dry well tank and add landscape gravel around it on all sides and at the bottom. 
  6. Then direct the end of the drainage pipe into the center of the dry well. You can even bear a hole on the side of the well to direct the pipe in.
  7. Finally, cover the dry well with turf and pebbles to make it aesthetically appealing.

Frequently Asked Questions

Which Adds More Drainage – French Drains or Dry Wells?

You can use both dry wells and French drains to remove water from a specific location. The two options remove water in different ways where French drains can move large amounts of surface water effectively. Dry wells drain into the soil directly underground which removes water from the immediate area where dry wells are installed.

What is More Expensive to Install a French Drain or a Dry Well?

French drains can be more expensive than dry wells depending on certain factors including the location of installation. The average cost to install a French drain ranges between $5,000 and $13,500. You will have to spend something between $1,581 and $4,750 for a dry well as the national average cost to construct a dry well is indicated as $2,956.

What Happens When Dry Well is Full?

Once the dry well reaches its full capacity, water will spill out over the side of the well and even the gutters. If leaves or any other debris gets into the line, it will clog the stones easily. This is a possible downside of a dry well since the leaves falling into the gutters can wash down into the dry well.

The clogs coming from sediments and debris along with the runoff will add to this. When the wastewater seeps out of the well, the undissolved solids will settle at the bottom. This will gradually prevent the draining over time and cause the well to overflow. So, it is necessary to be aware of this and keep the dry well as clean as possible.

How Do You Maintain a Dry Well?

It is important to maintain your dry well to avoid flooding on your property. If the dry well is filled with debris, you need to clean it unless you need to go for an expensive replacement.

  1. Inspect the gutters especially after storms to ensure that the water drains properly to the dry well.
  2. Filter out the leaves and sediment before the water reaches the dry well by placing gutter guards or screens on the roof downspouts.
  3. Try to avoid debris of trees from falling in the flow paths.
  4. Repair any damages in the gutters or downspouts.
  5. Do not place decks or structures over the dry well.

How Deep Does a French Drain Need to Be to Not Freeze?

If a French drain is installed correctly, it will begin at the depth of the base of the perimeter beam. It should have a minimum slope of 1% which is 1 inch in 8 feet. Since this is usually below the frost line the French drain will not freeze. Usually, when placed below the frost line the drains can perform around the year, especially in cold regions.


It is the homeowner who should determine what the best option is. If you are looking for an effective and affordable solution, a dry well will work for you. But a French drain offers better drainage and is also more costly depending on where you install it. If you cannot direct the French drain into a suitable discharge location, then you might have to use a sump pump to discharge the collected water.