20% 5% 10% 20% 30%

40%

50% 60%

70%

80% 90% 95% 100%

YE

LL

OW

MA

GE

NTA

CYA

N

BL

AC

K33 Why is having a properly func-tioning onlot system important?

Groundwater is the primary source of drinking waterin areas served by individual and community wells; therefore,keeping the groundwater free of contamination is very impor-tant. Water that carries sewage from a household or business toan onlot sewage disposal system (sometimes called a septicsystem) will eventually re-enter this same groundwater. Onlotsystems, when properly designed, operated and maintained,will treat this wastewater so that it may safely be used again.Onlot systems that are not functioning properly do not treatsewage to a level that is safe and can discharge improperlytreated sewage to the surface of the ground and/or to ground-

water. Improperly treated sewage carries bacteria and virusesknown to cause many human diseases, such as gastroenteritis,diarrhea and dysentery.

What soil conditions are neededto treat sewage?

About four feet of suitable soil is needed under thegravel layer to treat sewage. Good soil for sewage treatment isrelatively free of rock and not saturated with water. The soilstructure must allow the liquid waste to pass through at a suit-able rate. The waste must pass slowly enough to allow themicroorganisms time to feed on the harmful material, yet fastenough to dispose of the amount of liquid waste entering the

absorption area. While soils rich in clay treat sewage mosteffectively, the fine pores of many of these soils slow thedownward movement or percolation of sewage, which maycause backups to the surface of the ground. Soils rich in sandallow rapid percolation to dispose of sewage but do not holdthe sewage long enough to treat it adequately before it reach-es groundwater. Treatment continues in the soil until rock orsoil saturated with liquid is encountered. Rock allows sewageto move quickly into groundwater without proper treatment.Saturated soils do not provide the aerobic (oxygen rich) con-ditions needed by microorganisms to treat sewage. Partiallytreated sewage reaching either rock or saturated soils willenter the water supply. Any contaminants or disease-producingorganisms present in the sewage will be in the glass of wateryou drink from your polluted well. Viruses can survive ingroundwater in excess of one year.

UNDERSTANDING THE IMPORTANCE OF SOILSIN SITING AN ONLOT SYSTEM

INVESTIGATE BEFORE YOU INVESTPlanning to buy a lot that needs to have an onlot

sewage disposal system installed? Be sure to investigate beforeyou buy. Among other precautions, find out if:

• All state, county and local subdivision requirements, such as sewage planning, have been met and approved.• All permit requirements, such as zoning and building, have been met. • The lot you are considering qualifies for an onlot sewage disposal system permit from the local certified Sewage Enforcement Officer (SEO). (The buyer needs to be aware that a subdivision approval does not guarantee that each lot in the subdivision will qualify for a sewage permit. The buyer may want to require the seller to obtain a sewage permit first as a condition of the sale.)

If you have any questions or doubts about therequired permits or subdivision approvals for the lot youare considering, contact the local government officialswhere the lot is located. Be sure to contact the SEO.Remember, what may look like the dream lot could lead tonightmares and, possibly, financial ruin. So, investigate beforeyou invest!

Working with your local SEOThe onlot permit program is administered by a local

agency (township). This organization may be a municipality, amulti-municipal organization, or a county or joint county Depart-ment of Health. An SEO is the local agency employee responsi-ble for reviewing and approving permit applications and beingknowledgeable about onlot systems. While the SEO is trained byDEP and certified by the State Board for Certification of SewageEnforcement Officers, the SEO is actually an employee of thelocal agency, not DEP. To find out how to contact the localagency SEO, start with your local municipal office.

Getting your permitTo obtain a permit for an

onlot sewage system, these stepsmust be followed in the order listed:

1. The lot owner, or an agentfor the owner, applies for a permitthrough the SEO. If the lot is in a subdivi-sion, the lot owner should first ensure thatall other state, county and local planning,zoning and land use requirements have beenmet by checking with municipal officials.

2. The SEO measures slope and conducts soil profileexaminations and percolation tests to determine if the site issuitable for an onlot system. If suitable, the SEO determineswhich type of onlot system will work best. (The types of sys-tems are listed later in this document).

3. If the site is suitable, the SEO informs the lot owner oragent to proceed with the system design. The systemmust be designed with certain factors in mind,including site condi-tions, isolation dis-tances, perco-lation testresults

and the number of bedrooms in the home. (The SEO is specifical-ly prohibited from designing the system.)

4. Once the lot owner or agent has the design and plotplan, they are submitted as part of the permit application to theSEO. The SEO must approve or deny the permit within sevendays of receiving a complete application. If approved, the SEOissues the permit and the applicant may begin installing the sys-tem and building the home. If denied, the SEO notifies theapplicant and provides the opportunity to an appeal hearingbefore the local agency.

5. The SEO may oversee any step of the installation,but must inspect the completed system before it is covered.

Knowing the types ofonlot systems

There are five basic conventional onlot systems per-mitted for use on residential lots. They are:

• in-ground trench • in-ground seepage beds • subsurface sand filters • elevated sand mounds • spray irrigation

The type of system selected and permitted depends onthe site conditions and the type of soil on the lot.

Choosing an alternate systemIn some cases, when a lot does not qualify

for a conventional onlot disposal system, the lot owner maywish to consider an alternate system. There are a variety of alter-nate onlot system types DEP has approved over the years thatmay be appropriate. This list is updated periodically and is

available online at DEP's website(http://www.dep.state.pa.us/), PA Keyword "Wastewater."

Keep in mind, however, some lots just are not suitable forany type of disposal system due to inadequate soils, highwater table, steep slopes, or other important factors.Some alternate systems include:

• elevated sand mound bed on slopes between 12 and 15 percent • non-infiltration, evapotranspiration bedcontained within a greenhouse • separation of blackwater/greywater

sewage flows• flow equalization (commercial only)

• subsurface sand filter (trenches) • shallow absorption area with pressure distribution • peat based filter systems • leaching chambers • at-grade bed systems • the A/B soil system • various recirculating sand filters

There are specific requirements that must be metwhen using an alternate system. Contact your SEO or DEP forinformation about these requirements.

DEP also has guidelines for the development and useof experimental systems. Successful experimental systemseventually may be accepted as alternate systems, making themavailable for use at other difficult sites.

Observing the installationWhen you have the permit (which is valid for three

years), you are ready for the installation of your system. Besure to hire a reputable contractor because the best designedsystem can malfunction if not properly installed. Get writtenbids from potential contractors, ask for a list of references, andask professional associations or your local SEO if they knowthese contractors. You, too, should be somewhat aware of theproper installation procedures and observe the contractor'sactivities. Ask your local SEO for information about properinstallation procedures.

Once the onlot system is installed, the homeownerbecomes responsible for following proper operating and main-tenance procedures to prevent malfunctions and ensure long-term use of the system. See DEP's "Onlot System Operators andMaintenance (Homeowner's Guide)" available on the DEP web-site for additional information.

Signs of an onlot system introuble include:

• Toilet runs sluggish. • Sewer odors in the house and/or drinking water. • Illness, often to household visitors. • Sponginess around septic tank, distribution box ordosing tank and absorption area. • Surfacing raw sewage. • Dosing pump runs constantly or not at all. • Dosing tank alarm light is on. • Backup of sewage into laundry tubs or other fixtures.

Many of these signs listed will indicate an onlotsystem malfunction.

Preventing malfunctions Homeowners can help prevent malfunctions and

ensure the long-term use of their onlot system by doing thefollowing:

• Conserving water and reducing wasteflow into theseptic tank. • Having the septic tank pumped at least every 3-5 years, depending upon tank size and household size. • Avoiding putting chemicals in the septic system. • Not using the toilet to dispose of bulky, slowlydecomposing wastes. • Inspecting the septic tank, pipes and drainagefield annually. • Maintaining accurate records of the septic system (design, installation, location, inspections, pumpings,malfunctions, repairs.) • Preventing run-off from downspouts, sump pumps, and paved surfaces from getting into the septic system. • Keeping heavy vehicles, equipment and livestock away form the septic system. • Not planting trees and shrubs over or close to theseptic system.

CONTINUINGOPERATION

ANDMAINTENANCE

Onlot systems not only treat and dispose ofdomestic sewage from toilets; they also receive wastewaterfrom various other household fixtures, including baths,showers, kitchen sinks, garbage disposals, automatic dish-waters and laundries.

Conserving water and reducing the amount ofwasteflow from household activities is an important step toensuring long-term use. The more water-using devices in ahousehold, the greater the burden is on the onlot system.

Your Toilet is not a trash can Trillions of living, beneficial bacteria constantly

treat and decompose raw sewage in a septic system. Theeffectiveness of these bacteria can be impaired if harmfulsubstances and chemicals are put into the septic system.Harmful substances/chemicals include:

• oils and grease • gasoline • antifreeze • varnishes and paints and solvents • harsh drain and toilet bowl cleaners • laundry detergents with high sudsing elements • bleach • pesticides

Remember, what goes into your toilet and drainsmany eventually end up back in your drinking water. Soinstead of using caustic toilet bowl cleaners or bleach, trymild detergent or baking soda or one half cup of borax pergallon of water.

Also NEVER flush bulky, hard to decomposeitems such a sanitary napkins, diapers, paper towels, ciga-rette filters, plastics, eggshells, bones or coffee groundsdown the toilet because they can clog the system

CONSERVING WATER ANDREDUCING WASTEFLOW

Saving moneyA key reason to maintain your septic system is to

save money! Failing septic systems are expensive to repairor replace, and poor maintenance is often the culprit. Hav-ing your septic system inspected regularly (at least every 3years) is a bargain when you consider the cost of replacingthe entire system. Your system will need pumping (general-ly every 3 to 5 years), depending on how many people livein the house and the size of the system.

An unusable septic system or one in disrepair willlower your property value and could pose a legal liability.

Protecting health andthe environment

Other good reasons for safe treatment of sewageinclude preventing the spread of infection and disease andprotecting water resources. Typical pollutants in householdwastewater are nitrogen, phosphorus, and disease-causingbacteria and viruses. If a septic system is working properly,it will effectively remove most of these pollutants.

What does aninspection include?

• Locating the system.• Uncovering access holes.• Flushing the toilets.• Checking for signs of backup.• Measuring scum and sludge layers.• Identifying any leaks.• Inspecting mechanical components.• Pumping the tank if necessary.

Improper designor installation

Some soils provide excellent waste-water treatment; others don’t. For this reason, thedesign of the drainfield of a septic system isbased on the results of soil analysis. Homeownersand system designers sometimes underestimatethe significance of good soils or believe soils canhandle any volume of wastewater applied to them.Many failures can be attributed to having an under-sized drainfield or high seasonal groundwater table.Undersized septic tanks—another design failure—allowsolids to clog the drainfield and result in system failure.

If a septic tank isn’t watertight, water can leakinto and out of the system. Usually, water from the envi-ronment leaking into the system causes hydraulic overload-ing, taxing the system beyond its capabilities and causinginadequate treatment and sometimes sewage to flow up tothe ground surface.

Water leaking out of the septic tank is a significanthealth hazard because the leaking wastewater has not yet beentreated. Even when systems are properly designed, failuresdue to poor installation practices can occur. If the drainfield isnot properly leveled, wastewater can overload the system.

Heavy equipment can damage the drainfield dur-ing installation which can lead to soil compaction andreduce the wastewater infiltration rate. And if surfacedrainage isn’t diverted away from the field, it can flow intoand saturate the drainfield.

Care for your drainfieldYour drainfield is an important part of your septic

system. Here are a few things you should do to maintain it:

• Plant only grass over and near your septic system. Roots from nearby trees or shrubs might clog and damage the drainfield.• Don’t drive or park vehicles on any part ofyour septic system. Doing so can compact the soil in your drainfield or damage the pipes, tank, or other septic system components.• Keep roof drains, basement sump pump drains, and other rainwater or surface water drainage systems away from the drainfield. Flooding the drainfield with excessive water slows down or stops treatment processes and can cause plumbing fixtures to back up.

WHY SHOULD I MAINTAINMY SEPTIC SYSTEM?

Use Water Efficiently• Install high-efficiency showerheads• Fill the bathtub with only as much

water as you need• Turn off faucets while shaving or

brushing your teeth• Run the dishwasher and clothes

washer only when they’re full

• Use toilets to flush sanitary waste only(not kitty litter, diapers or other trash)

• Make sure all faucets are completelyturned off when not in use

• Maintain your plumbing to eliminate leaks• Replace old dishwashers, toilets and

washers with new, high-efficiency models