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1. Can I use my septic system during or after a flood?

Whenever the water table is high or your sewage system is threatened by flooding, there is a risk that sewage will back up into your home. The only way to prevent this backup is to relieve pressure on the system by using it less.

Once floodwaters have receded, there are several things homeowners should remember:

• Do not drink well water until it is tested.
• Do not use the sewage system until water in the soil absorption field is lower than the water level around the house.
• If possible, don't use the system if the soil is saturated and flooded. The wastewater will not be treated and will become a source of pollution. Conserve water as much as possible while the system restores itself and the water table falls.
• Flooding of the septic tank will have lifted the floating crust of fats and grease in the septic tank. Some of this scum may have floated and/or partially plugged the outlet tee. If the septic system backs up into the house, check the tank first for outlet blockage. Clean up any floodwater in the house without dumping it into the sink or toilet and allow enough time for the water to recede. Floodwaters from the house that are passed through or pumped through the septic tank will cause higher flows through the system. This may cause solids to transfer from the septic tank to the drainfield and will cause clogging.
• If sewage has backed up into the house, clean the area and disinfect the floor. Use a chlorine solution of a half cup of chlorine bleach to each gallon of water to disinfect the area thoroughly.

2. How do I know if my septic system was damaged by flooding, and how can I get it fixed?

• Signs of damage include settling or an inability to accept water. Most septic tanks are not damaged by flooding since they are below ground and completely covered. However, septic tanks and pump chambers can fill with silt and debris, and must be professionally cleaned. If the soil absorption field is clogged with silt, a new system may have to be installed.
• Have your septic tank professionally inspected and serviced if you suspect damage.
• Only trained OSS specialists should clean or repair septic tanks because tanks may contain dangerous gases. 
• Do not pump the tank during flooded or saturated drainfield conditions. At best, pumping the tank is only a temporary solution. Mud and silt may enter the tank and end up in the drainfield. Under worst conditions, pumping out a tank that is in saturated soil may cause it to "pop out" of the ground may damage the inlet and outlet pipes. (Likewise, recently installed systems may "pop out" of the ground more readily than older systems because the soil has not had enough time to settle and compact.) Only trained OSS professionals should pump the tank.
• Pump the septic system as soon as possible after the flood. Be sure to pump both the tank and lift station. This will remove silt and debris that may have washed into the system.
• Do not compact the soil over the soil absorption field by driving or operating equipment in the area. Do not dig into the tank or drainfield area while the soil is still wet or flooded. Saturated soil is especially susceptible to compaction, which can reduce the soil absorption field's ability to treat wastewater and lead to system failure.
• Examine any electrical connections for damage before restoring electricity.
• Be sure the septic tank's cover is secure and that inspection ports have not been blocked or damaged.
• Check the vegetation over your septic tank and soil absorption field. Repair erosion damage and sod or reseed areas as necessary to provide turf grass cover. 

3. Should I use an additive in my septic tank?

Most additives do not have any positive effect on your septic tank. Nothing you add to your tank will improve normal bacterial action.

4. When is an OSS permit needed?

You need an OSS permit (septic system permit) any time you construct, repair, replace, modify, connect to, or expand your septic system. You do not need an OSS permit when you:

• Replace a baffle in a septic tank.
• Fix a broken house sewer pipe.
• Replace a pump control float.
• Fix or replace septic risers, lids or inspection ports.
• Replace a septic pump.

Your OSS permit does not mean that you have met any other legal requirements like building codes or zoning ordinances. You must also comply with relevant permit requirements from other agencies before you begin work on your system. For example, you may need to get a land disturbance permit from Whatcom County Planning and Development Services. 

On-Site Sewage

5. Can I design my own OSS?

State and county sewage control regulations require that either a licensed OSS designer or Registered Professional Engineer design your OSS. The state issues Licenses for Designers and Engineers.

Washington State Department of Licensing

6. Can I install my own OSS after I obtain an OSS permit?

Whatcom County code requires that all OSS be installed by a licensed OSS installer; however, if you are the property owner and you will live in the home the OSS will serve, you can request an exemption from certification requirements. The request will be reviewed and if approved, you can install the OSS. We recommend that you hire a Licensed OSS Installer for complex systems, e.g. pressure systems or alternative systems.

Developers must hire a Licensed OSS Installer or obtain an OSS Installer's License through Whatcom County Health and Community Services to install OSS on properties they plan to develop and then sell.

Exemption From Certification Requirements (PDF)

7. Do you have a copy of my OSS permit?

Health and Community Services documents related to OSS and Drinking Water in Whatcom County can now be found online.

Related Documents

8. How do I clean up sewage that has backed up into my house?

Please see the following guidelines from the Washington State Department of Health in regards to sewage cleanup.

Cleaning Up a Sewage Spill

9. What are some signs that my OSS is failing?

Some warning signs of a failure are odors, surfacing sewage, soggy spots with lush green grass growth in the drain field or septic tank area, plumbing or septic tank backups, slow draining fixtures, or gurgling sounds in the plumbing system. If you suspect that your OSS is failing, contact us for assistance.

10. How can I find my septic tank?

If you have an as-built tank, locating the septic tank will be easy. If 1 is not available you or your pumper will need to use some investigative skills. If a crawl space is available you may determine where the plumbing leaves the foundation wall and then use a probe bar to find the tank. Use caution as fiberglass or polyethylene tanks can be ruptured with a probe bar. Probing works best if the tank is not more than 1-2 feet under the surface.

If a crawl space is not available, you can sometimes use the plumbing vents located in the roof. A plumbing vent may align with the exit point of the sewer line leading to the septic tank. If these options don't work it may be necessary to use an electronic detection device with a transmitter that can be flushed down the toilet.

11. What is the reserve area?

The reserve area is designated on your OSS Permit and is another area approved for the installation of a new drain field in case the main drain field fails. The reserve are must be kept clear of impermeable surfaces, e.g. buildings and pavement. If your OSS permit was issued more than 5 years ago, you may need to have your reserve area redesigned to meet current code requirements.