Save $ -Keep Your Septic System Sweet! 2/14/15
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How
can you keep your septic system working well?
Conserve water. Send the septic system
less than 50 gallons per bedroom per day,
and under 10 gallons per bedroom per hour: Spread out baths, showers, laundry,
etc. (8-min shower@2.5 gallons per minute=20gal, bath=washer=25-40gal,
flush=1-7gal).
Drain hot tubs[3]
& water beds elsewhere or over several days. Water softener
salts may or may not hurt;
minimize water with flow-based softener, not timer-based. Electronic softener
may work.[5]
Reverse osmosis purifiers create 1-9 times as much waste water as the
2-15 gallons of clean water they deliver per day.[6]
Drainfield handles moderate flows forever
(Long Term Acceptance Rate, LTAR). Wash water (graywater) has lots of bacteria
& soap; it needs to go to septic or other treatment.[8]
Don't flush what kills
bacteria:[9]
Paint, chemicals, gas, pesticide, medicine,
drain cleaner (11grams at a time ok), bleach (1.8gal ok).
Don't flush what bacteria
can't eat:
Oil, coffee grounds, plastic (e.g. floss, diapers), clay-based cat litter,
cigarette butts, paper except toilet paper.
These accumulate & must be pumped out. Powdered detergents often include
clays (zeolite, montmorillonite) which accumulate or clog soil.
Hair flows through & clogs soil. Septic additives don't help
& can hurt the drainfield.
Don't flush cat feces in
septic or sewer system: parasite hurts ocean species[15]
Install a water meter to measure water use.
(Biggest leaks can be toilets: Put food color in tank; does it appear in bowl?)
Find a pumper who will do the following
(yellow pages under Septic; they'll find tank electronically if needed): Measure
sludge & floating layers before pumping. After pumping, hose walls
& look for leaks.[16]
Replace concrete outflow baffle
(can corrode & let oil through) with PVC tee. Add a filter
where water leaves tank.
Have distribution box checked; it can tip or corrode. Have tank pumped every
3-5 years. Pump annually if you use a garbage disposal. While pumping,
water flowing into tank from drainfield means field
is waterlogged. Water trickling from house means a leak, or blockage.
What
are alternative costs if your septic system stops working?
The symptom of a problem is
water appearing at the lowest overflow point: a plumbing fixture or wet ground,
not always odor.[18]
Approximate cost
FREE Conserve water as
drastically as possible.
Better than free: saves $$. Install water meter & read daily or weekly.
$0-500 Make sure storm water
doesn't drain into septic system or onto drainfield.[20]
$0-1,500 Go away for as many
weeks as you can (vacation, friends, rent a house).
$1,500 Add pump or siphon[21] to send
liquid from tank intermittently. This "pressure dosing" can be as
good as alternating drainfields.
$1,500 Dig & divert
flows to a temporary drain line if you have a little space.
Chamber may be better than gravel.
$1,500 Add a 2nd
septic tank or replace with a 2-chamber model.
Add a filter.
$1,500 Replace any septic
tank that lets water leak in.
$2,500 Dig & divert flow
to another drainfield if you have enough
space.
$3,000 -9,000 Connect septic
outflow to community drainfield.
$10,000 Replace your septic
system with a home aerobic unit or other treatment.
$10,000 Replace soil &
drainpipes. (Hydrogen peroxide does not fix drainfield.[28])
$25,000 Connect to public
sewer & pay monthly bills.
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How do septic
systems work?
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What can go
wrong at each step?
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1
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Water & waste drain to
a septic tank (1,000-2,000 gallons, concrete, fiberglass or polyethylene).
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Internal baffles can
corrode, break, or leak, so oil & paper wash into drainfield
& clog it. Septic gas is dangerous; stay out & don't smoke near it.
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2
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Solids settle & light
things like oil & paper float in the tank. Many ingredients are slowly
broken down by bacteria.
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(a) Sending water too fast
doesn't leave liquid in tank long enough for solids & oils to separate
out, & may exceed percolation rate of soil.
(b) Omitting pumpouts lets solids or oils build up until they can wash
out to drainfield. See step 5.
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3
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Liquid flows out to a
distribution box and then to 300-500 feet of perforated pipes in gravel beds
in the soil (drainfield).[30]
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Trees & bushes within
20 feet
of drain lines can clog pipes with roots. (Remote camera can inspect pipes.)
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4
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Liquid spreads through
gravel & is then filtered by soil & treated by bacteria.[32]
Good bacteria digest nutrients & pathogens in the liquid & multiply,
forming a valuable biological mat in pores of soil & gravel.
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(a) Driving on drainfield compresses soil: water can't flow; bacteria
can't grow.
(b) If water in drainfield (rain plus septic system) exceeds percolation
rate of soil, water will back up in pipes or in soil.
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5
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Bacteria die after a normal
lifespan, re-opening pores, and are constantly replaced.
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Too many nutrients (from
problem 2) make biomat grow faster than it dies; it
becomes nearly impermeable, and water rises to surface or backs up into home.
(Soil auger can take sample to inspect biomat.
Infrared photos or sampling devices can measure flows & pollution.)
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6
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Clean liquid flows into
groundwater, including any caverns or channels below ground. Some systems
also reduce Nitrogen pollution[36]
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If pipes were installed too
close above rocks, then unfiltered liquid can reach rock channels &
pollute groundwater invisibly. If there is initially enough distance, biomat is a self-sealing barrier so invisible pollution
does not start later.
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Central sewers
fail more massively: Pipes crack, treatment can fail, sludge goes on soil as
thin as 6" over rock; pollution goes in streams & groundwater.[37]
©Stewards of
the Potomac Highlands, PotomacHighlandStewards.org,
an environmental nonprofit.
Full copy
with footnotes & sources on Listenv.homestead.com. OK to reprint if you reprint
this whole page.
Sources & Links
SFQ means Small Flows Quarterly, published by
National Small Flows Clearinghouse
Pipeline NSFC means the newsletter of that name published by National Small Flows Clearinghouse
Pipeline WVPSC means the newsletter of that name published by
the WV Public Service Commission
[3] "Homeowner's Guide to Septic
Systems" EPA-832-B-02-005, 2002, p.11
"Q+A,
Drainfield Inspection" SFQ Spring 2004
v.5 no.2, p. 42 and
"Letter
II" " SFQ Fall 2004 v.5 no.4 p.19 and
"Water
Softener Use Raises Questions for System Owners" Pipeline NSFC
Winter 2001 v.12 no.1. Page 4 says calcium keeps the sodium chloride from
clogging the drainfield. Page 6 says potassium
chloride may hurt bacteria less. No research is cited on whether bursts
of potassium or sodium hurt bacteria in normal anaerobic septic tanks.
[5] Electronic softener on incoming water pipe is
designed to precipitate calcium ions into aragonite, which leaves water soft,
does not cling to pipes, passes into drainfield and
soil. Opinions differ whether it works. The effect of aragonite on drainfields is unreported, but it dissolves readily in
slight acidity, which the biomat may have.
"the
system never completely clogs" in "Q+A, How to Extend the Life of
Your Drainfield" SFQ Summer 2003 v.4 no.3
p. 36 and
"Alternating
Drainfields" Technical Overview SFBLTO01 p. 3,
in SFQ Spring 2004 v.5 no.2, after p.28 and
"Wastewater
Infiltration into Soil" Winter 2004 v.5 no.1, p. 29
[8] "Graywater
Use" SFQ Winter 2001 v.2 no.1 p. 20
[9] Business use needs over-sized system, because
of more organic waste per gallon and wider variations around the average flows.
"The Best Wastewater Systems Consider Flow Rate and Waste Strength" SFQ
Spring 2000 v.1 no.2 p.14
"Mystery
behind PPCPs" SFQ Winter 2004 v.5 no.1, p. 14 and
"Maine
Passes Bill to Deal with Unused Medications" SFQ Summer 2004 v.5
no.3, p.8
"Septic
Tank Additives" SFQ Winter 2002 v.3 no.1, p. 27
"Q+A,
Drainfield Inspection" SFQ Spring 2004
v.5 no.2, p. 42
"Septic
Tank Additives" SFQ Winter 2002 v.3 no.1, p. 26 and
"Grease
Traps" SFQ Spring 2002 v.3 no.2, p. 36.
EPA
and many plumbers say additives break down solids so much they stay suspended
and clog the drainfield, instead of dropping to
bottom of tank, “additives are not necessary... may decrease the
performance of septic drainfields... threat to soil
structure and groundwater.” https://www.epa.gov/septic/frequent-questions-septic-systems
[16]
"Pumping Your Septic Tank"
Washington Sea Grant Program 3/03 and
"Watertight Tanks" SFQ
Summer 2004 v.5 no.3, p. 12
"Effluent
Filters" SFQ Winter 2003 v.4 no.1, p. 38
[18] "Offensive Odors Don't Always Mean Septic
System Failure" SFQ Fall 2004 v.5 no.4 p.30
"Alternating
Drainfields" Technical Overview SFBLTO01 p. 7,
in SFQ Spring 2004 v.5 no.2, after p.28
[20]
Water flows in soil at a limited rate (percolation rate). If
total of rain plus flushed water exceeds this rate, water backs up in pipes;
reduce the load by sending rainwater elsewhere.
[21]
Pipeline NSFC Summer 1995 v.6
no.3, p. 5
"Many
references ... suggest pressure dosing is equivalent to installing alternate drainfields"
in
"Alternating Drainfields" Technical
Overview SFBLTO01 p. 5, in SFQ Spring 2004 v.5 no.2, after p.28 and
"Q+A, How to Extend the Life of Your Drainfield" SFQ Summer 2003 v.4 no.3 p. 37 and
"Role
of Biomats in Wastewater Treatment" SFQ
Fall 2001 v.2 no.4, p.36
but
"Letter III" says iron & sulfur accumulate in soil pores every
time drainfield is saturated; SFQ Fall 2004
v.5 no.4 p.19
"Alternating
Drainfields" Technical Overview SFBLTO01 p. 6,
in SFQ Spring 2004 v.5 no.2, after p.28
"Gravelless System and Chamber System" SFQ Fall
2000 v.1 no.4, p 47 and
"Letter
to the Editor" SFQ Summer 2004 v.5 no.3, p. 41 shows doubts about
chamber system
"Soil
Characteristics" Pipeline NSFC Spring 2002 v.13 no.2 p.5 and
"Chamber
Systems are Easy to Install" SFQ Fall 2003 v.4 no.4, p. 50 and
"Wastewater
Infiltration into Soil" Winter 2004 v.5 no.1, p.38 and
"Gravelless and Chamber Systems" Pipeline NSFC
Summer 2001 v.12 no.3, p. 1
"High-Strength
Flows" Pipeline NSFC Fall 2003 v.14 no.4, p. 4 and
"Development
of an Enhanced Performance Septic Tank" SFQ Winter 2001 v.2 no.1,
p. 37
"STEP
System Clears the Air" SFQ Winter 2001 v.2 no.1, p. 28 and
"Small-Diameter
Gravity Sewers" SFQ Spring 2001 v. 2 no.2, p. 24 and
"Sewage
Disposal" Pipeline WVPSC Nov-Dec 2003 v.1 no.6
[28] "Hydrogen Peroxide Not Recommended to
Unclog Failed Drainfields" because it creates
impermeable layer of fine sediment; SFQ Spring 2000 v.1 no.2 p.14
Cost
includes $16,000 pipes, $3,000 expanding treatment plant, $3,000 closing
septic, $3,000 higher monthly bills
[30]
Tire chips are an alternative to gravel
"Tire Chips, a Growing Trend as Aggregate in Soil Absorption Systems"
SFQ Fall 2003 v.4 no.4 p.14
"Landscaping
Options" SFQ Spring 2004 v.5 no.2, p. 21
[32] "Soil
Absorption Systems" Technical Overview SFBLTO03, in SFQ Fall 2004
v.5 no.4, after p.32 has much information on drainfields.
It says research shows that 24" of soil below trench, & above water
table or rock (whichever is higher), are enough to treat effluent. It notes
area of trench bottoms is average or peak gallons/day from the house, divided
by gallons/square foot/day which the soil can absorb.
"Alternating
Drainfields" Technical Overview SFBLTO01 p. 3,
in SFQ Spring 2004 v.5 no.2, after p.28 and
"In-Ground
Dispersal of Wastewater Effluent" SFQ Spring 2003 v.4 no.2, p. 32
and
"Wastewater
Infiltration into Soil" Winter 2004 v.5 no.1, p. 29 and
"Role
of Biomats in Wastewater Treatment" SFQ
Fall 2001 v.2 no.4, p.36
"Q+A,
Drainfield Inspection" SFQ Spring 2004
v.5 no.2, p. 42
"Monitoring
Effluent Plumes" SFQ Summer 2000 v.1 no.3, p. 40 and
"Septic
System Performance Analysis Utilizing Color Infrared Aerial Photography,
Berkeley County WV" by Environmental Research Inc, Linden VA, 1996 and
"Arkansas
Sanitarian Uses Infrared Technology to Track Down Sewage" SFQ
Spring 2000 v.1 no.2 p.22
[37] "Think
Septics Are Always Bad? Then You Don't Know
Sewage" SFQ Fall 2004 v.5 no.4 p.19 reprinted from Bay Journal May
2004 and
"When Systems Fail" SFQ
Fall 2004 v.5 no.4 p.20 and
West Virginia State Rules 47-31
App.B-A-2.2 expect well-designed new 8" diameter sewer pipes to leak 1,600
gallons/day/mile; and
Optimizing Operation, Maintenance, and
Rehabilitation of Sanitary Sewer Collection Systems New England Interstate
Water Pollution Control Commission 12/03 https://web.archive.org/web/20061006220857if_/http://www.neiwpcc.org/Index.htm?omrmanual.htm~mainFrame "Many collection systems are
maintained by a public works department charged with various functions, such as
street, sidewalk, storm drain, and sometimes water utility maintenance. Money
is usually spent where the ratepayer can see the results... The lack of proper
maintenance has resulted in deteriorated sewers with subsequent basement
backups, overflows, cave-ins, hydraulic overloads at treatment plants, and
other safety, health, and environmental problems. As one of the most serious
and environmentally threatening problems, sanitary sewer overflows - or SSOs -
are a frequent cause of water quality violations and are a threat to public
health and the environment." p. 1-2. " Since these
sewers[crossing streams] are often in remote locations, they are susceptible to
vandalism and can overflow for long periods of time without detection."
p. 7-3 and
Report
to Congress: Impacts and Control of CSOs and SSOs EPA 8/24/04 https://web.archive.org/web/20130216070527/https://cfpub2.epa.gov/npdes/cso/cpolicy_report2004.cfm