Armchair Builder

Water and Sewer Service and Under Slab Plumbing

How to Build a Home, Step 30

Typically, your water and sewer service and underslab plumbing will be installed after your new home foundation has been backfilled.  Do you have any idea why we install them at this point?  What are the typical quality checks required to ensure a trouble-free installation for years to come?  Today we continue our blog series, How to Build a Home, with the installation of water and sewer service and under slab plumbing.

Water and Sewer Service Installation for Home

Water and Sewer Service Installation

Water and Sewer Service Scheduling

There are so many activities that need to be completed on a new home.  Sure, it is possible to install the water and sewer service at any time.  However, from a safety and quality standpoint, it makes total sense to have them go in right after backfill of the foundation.  Here’s why…

  • Creates a trench in the yard which can be dangerous for other workers
  • Once the trench is backfilled, it needs to settle out prior to landscaping…the more time it has the settle out naturally, the better
  • Building Materials – at this point, there are no building materials in the way…but trusses and lumber are coming soon

We also schedule the under slab plumbing to be installed at this point since the plumbing contractor is on site…this saves the cost of a return trip and gets the home ready for the concrete slab pour


Have you ever had a problem with your water and sewer service in your home?  If a snake can’t be used to dislodge a problem in the pipe, it will typically need to be dug up for repair.  The heavy equipment and dirt from the excavation makes a huge mess of your beautiful yard.  And if for some reason your builder located the water and sewer service underneath the driveway or patio, you’ll have an even bigger mess and expense.  So, make sure your contractor doesn’t install these services under any concrete or asphalt.  You will also want to have your contractor permanently mark the curb showing the locations at the street to make them easier to find in the future.

Mark Plot Plan

Whether you have city water and sewer service or private well and septic, be sure to mark the pipe locations on your engineered plot plan.  By including the locations with dimensions on your plan (including any changes in direction of the pipe), underground pipes can be found easily in the future should a repair be required.

Quality Checks

Here are some quick quality checks for your water and sewer service and under slab plumbing to improve your chances of a trouble-free installation.

  • Confirm the plumbing contractor will be scheduling the inspection with the local building department or county
  • Plumbing contractor must seal up the foundation wall if pipes penetrate through (this should come with a minimum one year warranty)
  • Backfill material surrounding the pipe must be free from rocks, building materials, concrete…etc.
  • Rocky or unstable soil must be over excavated by at least two pipe diameters and filled with a suitable compacted granular material
  • Discuss locations where services enter the basement.  Ideally, the services will come into the basement in an unfinished area
  • Cleanouts – discuss sewer cleanout location in yard to avoid driveway and walkways if possible.  Freeze-thaw cycles can lift slabs and cause problems for cleanouts
  • Pipe Protection – pipes passing through concrete or block walls shall be protected against external corrosion by a plastic sheathing or wrapping
  • Water Pipe – shall be at least six inches below the frost line

Scopes of Work and Specifications

There are a couple of things you will want to include in your scopes of work and specifications for water and sewer service installation and under slab plumbing.  Here are the most overlooked items…

  • Warranty – make sure you get a one year warranty covering all materials and workmanship
  • Inspections – the contractor should call in all inspections and confirm approvals
  • Safety – contractor should be responsible for ensuring all work is performed per OSHA safety requirements and is responsible for calling in the underground utility locate and checking on the “all clear” before digging
  • Materials – all required material should be included in the price quoted…including all stone
  • Water Pumping – the nature of this building activity sometimes requires water to be pumped from the excavation…include this in the scope of work for the contractor
  • No Extra Charges Clause – make sure your contract or scopes of work state that no additional work will be performed without first obtaining approval from the owner in writing agreeing to the extra costs

If you are building your own home and need a scopes of work and specification for all building activities, stop by our ESTORE.  We also have The Builder’s Daily Construction Guide that gives more detail for the day-to-day management of your new home building project.  Stay tuned to our blog as we continue our series on how to build a home.




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