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Building A New Home? Northern Virginia Guide to Septic Systems: What You Should Know Before Submitting Offer for Land Purchase

New Construction Homes by Natasha Lingle

I understand that septic systems might be the last thing on your mind when you are planing to build a gorgeous new home in McLean, Vienna or Great Falls. But the approval of the septic system might be one of the most important parts of the building process.

If public sewer is not available, no house can be constructed without approved septic system!

What is Septic System?

Septic system is underground waste treatment structure installed in the areas where public sewer is not available.

Septic systems come in all shapes, sizes, types and capacities ranging from a simple gravity conventional system for a 1 bedroom hunting cabin to a large communal alternative onsite sewage system serving more than 300 homes, but they all have one thing in common – they all have to be approved by the County’s Health Department.

All conventional and alternative septic systems are soil based disposal systems; therefore, the approval of the systems and their types will depend on the soil study that includes soil percolation test. The location of the house will be dictated by the placement of the septic system, and the location of the septic will depend on the results of the soil test.

If the soil test is unsatisfactory, NO house can be built on the property!

The buyers who are looking to buy property as land, will be confronted with two common scenarios:

  1. A property is sold as a lot with a “teardown” house that is already served by the septic system.
  2. The lot is sold as undeveloped or unimproved property.

For the lot with the existing system, it is important to check if the property has an area that is saved as a reserve (this area can be used for a possible extension of an existing system or for installation of a new system). As a first step of investigating the lot, it might be helpful to check on the number of bathrooms that the current septic system supports.  Why is this important? If in the past the system was approved to serve only 2 or 3 bedrooms, there is no guarantee that today the county will issue an approval for a brand new system that will serve the number of bathrooms desired, or will approve extension to the system currently in place.

REMEMBER: the most likely outcome is that the county will request abandonment of the current septic and an installation of a brand new system! The permits to abandon an existing system will have to be filed with the Fairfax County’s Health Department either by the seller or you as a new owner.

Also Read:

How to Vet A Parcel and Buy A Perfect Lot in Northern Virginia: 8 Land Purchasing Questions to Ask

Permits to construct or repair onsite sewage (septic) system

The permits to construct or repair onsite sewage system are not transferable between the owners. These permits are:

  • Issued to a single owner and not transferable between the owners
  • Valid for 18 months
  • Can be extended once for an additional 18 months
  • All work must be completed before extension expires

Certification Letters

What if the land is sold as undeveloped or unimproved?

As a contingency to the Contract For Purchase of Unimproved Property (Virginia Association of Realtors form 650), the seller has to provide Certification Letter issued by the Fairfax County’s Health Department.

This letter must show that soil test was performed and a septic system for a residential dwelling can be constructed. In addition, a plat showing the exact location for proposed septic system has to be attached. The Certification Letter will list property’s address, the name of the owner and the number of bathrooms allowed.

The higher the number of approved bathrooms, the more value the lot has.

Certification Letters:

  • Issued to a single owner
  • Transferable between the owners
  • Do not expire
  • Guaranty that system can be installed with a defined capacity
  • Do not guaranty system type
  • Can be null and void if property lines change or site is disturbed

When a seller or seller’s agent doesn’t provide certification letter for an approved septic, the trip to the county will be needed. If the septic was not approved, then it might take between 2-3 months to get an approval.

In order to protect yourself from a disappointing lot purchase, make sure the Contract For Purchase of Unimproved Property has these possible contingencies:

  • Reviewing of septic Certification Letter for unimproved land.
  • Obtaining permits for construction of Septic System.
  • Reviewing of Plat by certified building engineer.

Bottom Line

When buying land for a construction of new home, make sure to pay close attention to Septic System. The Contract has to include contingencies on the ability to pass a percolation test and/or obtain permits for construction of septic system. And of cause, hire a knowledgeable real estate agent who will take time to investigate the lot by doing a research at the Health Department, consulting with Fairfax County representatives, and will put you in touch with reliable septic specialist and an engineer. If you have any questions, feel free to Contact Me.

Are you ready to make a move? Check out these lots for Sale in:




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Meet The Agent

Natasha Lingle is an energetic and personable real estate professional with a proven track record of success representing home buyers, sellers and investors throughout Northern Virginia. Natasha is known for her deep knowledge of the local market, tenacity, strong negotiating skills, honesty and integrity. Whether providing expert guidance to buyers or creating custom marketing plans for the sellers, Natasha delivers the highest level of customer service to all her clients.

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