In the United States, a depth of 36 inches (three feet) for underground water lines is the accepted industry standard. This depth varies from location to location based on local conditions. In areas with colder winters, they may be buried deeper to prevent frozen well water pipes : This is usually at least six inches below the frost level. The International Plumbing Code calls for a minimum of 12 inches below grade.

Because decomposed granite is a durable material, a crushed rock or gravel base is optional as long as the DG is properly installed and compacted. However, installing a base is a good idea because it will ensure proper drainage and stability and act as a weed suppressant (although you may still occasionally have to pull weeds). Installing an adequate base can also increase the durability of driveways and walkways. If you forego the paver base or gravel underneath, line the area with landscaping fabric to avoid weeds.

The average cost for pool excavation is $2,500. This cost can range from $450 to $4,500, depending on the pool shape and size, time of year, and any need to move buried utilities. 

When excavating for your pool, you might have to move existing utilities. You can expect to pay an additional $15 to $25 per linear foot to move gas lines. To move a septic system, it’ll cost an additional $2,000 to $20,000. A pool that is 10 feet by 12 feet averages $450 to excavate, and a 20-foot-by-40-foot pool averages $3,020.

Directional drilling is complex and requires training to use the advanced machinery. It can be challenging to monitor the position of the drill since there’s no direct line of sight. Directional drilling can also be more expensive with a cost of $10 to $30 per linear foot compared to $5 to $12 per linear foot for trenching.