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SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR
SEPTIC CARE INSTRUCTIONS
SEPTIC D-BOX INSPECTION
SEPTIC DRAINFIELD FAILURE DIAGNOSIS
SEPTIC DYE TEST PROCEDURE
SEPTIC FAILURE SIGNS
SEPTIC INSPECTION & TEST GUIDE
SEPTIC LIFE EXPECTANCY
SEPTIC SUPPLIES & PARTS
SEPTIC SYSTEM DESIGN ALTERNATIVES
SEPTIC SYSTEM DESIGN BASICS
SEPTIC SYSTEMS, HOME BUYERS GUIDE to
SEPTIC SYSTEM SAFETY WARNINGS
SEPTIC TREATMENTS & CHEMICALS
SEWAGE BACKUP PREVENTION
SEWAGE EJECTOR / GRINDER PUMPS
SEWER GAS ODORS
SEWER LINE REPLACEMENT
SINKHOLES, WARNING SIGNS
SOAKAWAY BED FAILURE DIAGNOSIS
SULPHUR & SEWER GAS SMELL SOURCES
TOILETS, INSPECT, INSTALL, REPAIR
TRAPS on PLUMBING FIXTURES
TREATMENTS & CHEMICALS, SEPTIC
VIDEO GUIDES: Septic Videos
WASHING MACHINES & SEPTIC SYSTEMS
WATER SOFTENERS & CONDITIONERS
WATER SUPPLY & DRAIN PIPING
WASTEWATER TREATMENT BASICS
WATER, WELLS, WATER TANKS: TESTING GUIDE
WINTERIZE A BUILDING
Septic Loading and Dye Test Procedure for home buyers. This document provides advice for home buyers who are buying a property with a private septic system, that is, a septic tank and a leach field or drainfield or similar soil absorption system. This is 5-3 SEPTIC SYSETM LOADING & DYE TEST, what is a septic dye test, how should it be performed, what are its use and its limitations.
Chapter 5 in answers detail: questions to ask about the septic system, how to perform the visual septic inspection, ordering the loading and septic dye test (the too-obvious results of a dye test at a problem site are in the photo at left), pumping the septic tank, and finding additional information about the septic system. We explain how to be sure your septic inspection and septic test are conducted properly.
We tell you where to get more septic system information about a given property, and we warn of unsanitary or dangerous site conditions.
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Hire your own septic test consultant who has experience with and is familiar with septic loading and dye testing standards, a licensed septic inspector (in states which license this specialty such as MA), or a licensed septic system installer, who performs a great deal of work in the particular town. They can give you advice as to the condition of the soils and septic systems In the area and what might be expected (especially pertaining to costs) if/when you find problems with the existing system.
This photo shows a small property bordering on a river. We were told that a "new septic system" was installed but I could not see where a conventional tank and drainfield could possibly fit except below the driveway.
Because of the nearly overwhelming temptation at such sites to pipe septic effluent directly into the river, we performed a septic loading and dye test to see if the river would turn red. The river did not quickly turn red but after less than 100 gallons of water had been run into the septic system our red septic dye appeared at the basement entry platform at the edge of the driveway, as shown in the photo used at the top of this page.
Warning:: Unfortunately many of the people performing these tests perform only a perfunctory test such as a low-water volume test (50 gallons is meaningless) or use an insufficient amount of tracer septic dye.
Therefore, the conclusions reached from these tests are often misleading. Be sure your test is performed by an expert and that an adequate volume of water is used. We specify no less than 50 gallons per bedroom or 250 gallons, whichever is greater.
Warning: if you hire a separate consultant only to perform the septic inspection and dye test you're at risk of getting a bad deal. It takes time to get enough water into the system to perform a reasonably aggressive test. It's economical to do this test when it is overlapped with other work at the site (like a home inspection).
But someone coming to the site just to do the septic test is not going to wait around for 2+ hours for water to run into the system - you're likely to get an inadequate test. If you must use a third party just for this test be sure to review the test parameters and agree on them ahead of time.
Warning: Do not pump the septic tank before the loading and dye test. Depending on its size an empty septic tank could require 2-3 days' worth of water to re-fill the tank. An empty tank means that the "loading water" run into the system during the dye test procedure is simply filling the tank rather than testing the ability of the drain field to absorb effluent.
5-3a WHAT'S A DYE TEST? What is a Septic Dye Test?
This procedure puts a test volume of water into the system to look for evidence of a blocked pipe or for breakout of septic effluent at the yard surface - indications of the need for repair. If you are looking at a completely new home and septic system you might omit this test but don't assume that new systems are immune to failures.
Pipes settle and break or systems can be improperly installed. If the tank was pumped immediately before your inspection you should be suspicious, and you might defer the loading and dye test as it may be unable to put enough water into the system to test the drain fields. The dye itself is just a coloring agent to identify water that may appear at the yard surface. It's the test volume of water that's important.
If the septic dye appears on the ground or appears in a brook or catch basin the septic system is in failure. Further investigation will be needed to determine the extent of septic repairs needed, though an informed inspector can often make a reasonable guess about what will be needed: a complete septic field replacement or more limited repairs.
The common septic testing dyes used are green or red depending on the environment. We have seen dye breakout in as little as 15-30 minutes in many instances where there was no pre-existing wet spot but where subsequent excavation confirmed that the system was either damaged or in failure. In unusual cases septic dye may appear at nearby waterways as much as five days after the test has been performed.
The first or left-hand photograph shows green septic dye appearing on a leafy yard surface near the drainfield during a septic loading and dye test. The second photo shows red septic dye appearing up through a modest snow cover during a winter test of a septic system using septic dye. Use of florescent dyes permits detection of even very dilute concentrations of dye, but usually the color and sheen of the dye are unmistakable without requiring UV lighting.
See Performing a Septic Loading and Dye Test, for complete details of the septic loading and dye test procedure, test data forms, septic loading test water volumes, septic tracer dye quantities, critical observations.
Warning: if dyed effluent or water does not break out on the property surface, this does not necessarily mean the system is functioning or will function properly in the future. There are certainly cases in which effluent does not appear at the surface for some time, possibly up to five days, and there are other defects which predict upcoming expensive repair or replacement of the system but which are not detected by loading the drain field.
National data collected among professional home inspectors between 1985 and 1995 indicated that a significant number of inspectors performing dye tests discovered total failure of the septic system within 20 to 30 minutes of beginning testing.
We agree that a dye test is by no means a complete test of a system, that the other measures suggested here are extremely valuable, and that the volume of water used is critical: too little or too much can both be serious mistakes.
If a wet area or soggy area is present, dye has been found to appear in the short time indicated. However beware: NYS DEC has found dye appearing in nearby streams as late as five days following a septic dye test in cases where effluent migrates through considerable ground area before entering a stream.
Warning this test should not normally be attempted. Placing 1000 gallons of water into a septic system in two hours is likely to exceed its design parameters, and in the case of certain systems, it could actually damage the system. While all inspections and tests should aggressively seek to protect the interests of the parties involved by being thorough, a test which exceeds system design parameters would be improper.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
Design Manuals for Septic Systems
Onsite Wastewater Disposal Books