French Drain Service

Water finds every weakness in your foundation. Heavy rain saturates soil around your home. Spring snowmelt raises groundwater levels. Poor drainage directs water straight toward your basement or crawl space. Without proper drainage systems, water accumulates where it causes the most damage—against your foundation and under your home.

French drains protect your property by intercepting water and channeling it away from vulnerable areas. Foundations First Idaho installs professional French drain systems for crawl spaces, basements, and exterior applications throughout Boise, Meridian, Nampa, Caldwell, and the Treasure Valley. With over 40 years of combined experience in foundation repair and waterproofing, we understand how water moves through Treasure Valley soils and how to stop it from damaging your home.

Foundation and crawl space work is our specialty, not a side service. Over 40 years of combined experience has taught us how water behaves in Treasure Valley conditions and how to design drainage systems that work reliably in our soil types and climate.

We focus exclusively on foundation repair, waterproofing, and related services. This specialization means we understand how French drains integrate with foundation repairs, crack sealing, and moisture control systems. Our installations protect your home’s structure, not just manage surface water.

Every installation is warrantied, giving you confidence in our work. We offer financing options to make necessary foundation protection accessible when your home needs it. Our goal is solving your water problems completely with systems that perform reliably for decades.

Foundations First Idaho serves homeowners across the Treasure Valley, including Boise, Meridian, Nampa, and Caldwell. We understand local construction methods, soil conditions, and the seasonal water challenges that affect homes in this region.

This local knowledge helps us design French drain systems specifically suited to Treasure Valley properties. We’ve installed hundreds of drainage systems in homes facing the same clay soils, water tables, and seasonal moisture patterns your property experiences.

French drain effectiveness depends entirely on correct installation. Improper slope allows water to pool instead of flowing to discharge points. Insufficient gravel restricts water flow into the system. Wrong pipe types or poor connections create failure points where systems clog or leak.

Prep for install: Locate the area where the drainage system will be installed per the sketch. Look for the highest point and the lowest point of the crawl space. The lowest point will be where the drain ends and the highest is where you want to start the drain.

At the high point, start digging a trench about 4 inches in depth. Trenching towards the low point, you will want to have at least a 1% fall every 10ft. 

Installation: Once the trench is all dug out, set the perforated sock pipe in the trench (doesn’t matter if you start from the high or low point). Make sure the pipe has a fall/slope, you can do this by using a level or doing a flood test. *Spread the dirt from digging the trench in the crawl away from the trench if you can, otherwise you may have to remove it from the site. Based on the soil, install a thin base layer of clean river rock.

Once the pipe is set and made sure it has fall, backfill the trench with clean river rock.

• Lay down plastic for dirt/concrete to keep the work area clean and organized. 
• Mark out where the pipe is to be installed and how much you need to demo. 
• Break out the slab 10 inches off the foundation where the drain is going to be installed. 
• Dig 4”-6” down from the face of the footing at the starting point and have a 1% fall towards the low point(end). 
• Once the trench is all dug out, place a small layer of clean river rock at the base of the trench. 
• Set the pipe in the trench and backfill with clean river rock to the bottom of the concrete slab. 
• Place drainage/dimple mat 4” up the stem wall and halfway in the trench. Lay 6-mil clear plastic over the top of the dimple mat/ river rock. 
• Mix and re-pour concrete, match the existing slab. 
• Remove dirt/concrete and clean up.

Installing a French drain exterior is similar to a crawl space install. Before digging, make sure you’re not running into any water, gas, or power lines.

• Trench dig exterior where the drain pipe is going to be installed per sketch. The trench should be about 12”-18” deep and 9” wide. The trench should have a 1% fall. 
• Depending on what was sold, we will have either a catch basin discharge or a pop-up discharge at the end of the French drain system. 
• Once the trench is all prepped, lay down a small base layer of clean river rock. 
• Install the basin/pop-up.
  • Drill ¼” holes around the bottom and sides of the basin.
• Set the pipe in the trench and make sure it has fall (flood test). 
• Connect the pipe to the discharge (pop-up/catch basin). 
• Back-fil the trench/ discharge with clean river rock (unless specified, relocate/remove dirt from the site). 
  • If installing triple wall pipe then landscaping fabric will need to be installed before any river rock is laid down. If installing perforated sock pipe is to be installed, you don’t need the landscape fabric.