Dry wells and french drains are both used to manage water on a property. In this blog post, we will discuss dry well vs french drain so you can decide which one would be best for your needs.
A dry well is a dry hole dug in the ground, which has been lined with waterproof material. This type of excavation is typically used to reduce groundwater pressure against the bottom of an existing structure such as a building foundation and can be effective for preventing frost heave.
A dry well can also serve as an infiltration trench that collects rainwater runoff from a roof or parking lot. In contrast, french drains are trenches that collect water draining off the soil surface before it can infiltrate into the ground below your house or seep back toward your house through cracks in its foundation.
French drains are often installed under slabs on grade foundations at their perimeter (i.e., where they meet exterior walls). They are used to route water to specific areas of your property, unlike dry wells which drain standing water into the soil.
When to Install a Dry Well
A dry well is a good choice when you need to drain water out of your yard but there are no nearby ponds or storm drains to dig a trench drain towards.
Dry wells work by draining the standing water down into the ground and soil. The more surface water that needs to be drained the deeper the well should be dug so it does not also flood during heavy rains.
The gravel will slowly drain the excess water slowly over time so is filtered back into the soil without damaging the landscaping.
One downside of a dry well is that it does not collect water on its own – you will need a drainpipe or catch basin to collect water and carry it to the dry well.
When to Install a French Drain
A french drain is a popular alternative to a drywell and a better choice for surface drains in some cases. French drains can route standing water towards a storm drain, a pond, river or another ideal drainage area.
Unlike dry wells which drain water deep into the ground, a french drain carries water underground in a perforated pipe. This allows you to solve a backyard drainage problem and have runoff water drain into a local water source or drain
Installing Both Dry Wells and French Drains
In some circumstances, it makes sense to install a dry well and a french drain. If you want to dry out a wet area on your property while also directing water away from the property, then both dry wells and french drains can be used.
In this scenario, it is best if you install dry wells around the perimeter of the property and have them drain into a french drainage system in another part of your yard that will route surface runoff into the dry well pit with a downspout drain.
An example of this would be to dry out a garden with dry well while directing rainwater runoff from the roof into your french drain system.
You should always consult an engineer or contractor when designing and installing dry wells, french drains and other water management systems on your property as they have special training in these types of projects.
Which is Better – Our Final Say
Many homeowners want to know which is better – a french drain, sump pump or dry well?
A dry well is an effective and affordable way to drain surface water away from your property. French drains are another option that allow for better drainage, but they can be more expensive than dry wells depending on where you install them. A french drain may need a pump if it cannot route runoff into the ground under your house or towards some other nearby.
Frequently Asked Questions
Which adds more drainage – french drains or dry wells?
Both dry wells and french drains can be used to help remove water from your property. French drains are more effective at moving large amounts of surface runoff, while dry wells tend to drain into the ground directly below them which gives better drainage around the immediate area where dry wells have been installed
What is the difference between a dry well and a French drain?
The difference between dry wells and french drains are that dry wells move water into the soil, while french drains are a more sophisticated drainage system that route runoff towards another location on your property where the surface water will be drained.