Colorado only - Infiltrator Quick4 leach field chambers

*  Strip all topsoil from atop components and stockpile for revegetation later
*  Return all soil, mounding atop leach field to encourage rain to drain away
*  Keep all livestock, vehicles, and snow storage OFF tank and leach field
*  Limit field runs (rows) to 12 or 13 chambers for about 50 feet total length
*  Always bring effluent pipe in top of chamber end cap, never into the bottom
*  Install large granite or durable ceramic tile underneath inlet for splash plate
*  Always ventilate the ends of every leach field pipe run or set of chambers
*  Loosen 'scarify' soil at least one foot in base of trench before backfilling
*  Add gravel into base of trench and atop chambers to improve longevity
*  Geotextile fabric prevents soil intrusion into gravel from above & sides
*  Never install geofabric in the bottom of any trench or septic leach field
*  Septic tank up to 10 feet away and leach fields 20+ feet from foundation
*  Leach field, especially pipe-in-gravel, should be 20+ feet away from trees
*  Never plant bushes or deep-rooting fescue, dichondra, brome, or rye atop
*  Never drive over a septic tank or leach field - chambers perpendicular only

All 'gravel-less' leach field chamber system brands function by the same set of physical limitations, regardless of marketing claims. Installation tips are not required, but there are always 'good, better, best' methods of approaching any construction project. 'Good enough' with chambers is digging a level trench and backfilling atop with native soil. 'Better' is to scarify (loosen and rake) the soil in base of trench to a depth of at least one foot before installing chambers. 'Best practice' is adding at least 6 inches of crushed washed 3/4 inch nominal gravel atop scarified soil to ensure long-term percolation and best sewage treatment. Your local quarry may refer to septic system leach field gravel as a #5 or a #57. The #5 translates as "crushed stones 1 inch or less". Sometimes, they don't bother to "wash" it to remove sand and fines. The #57 is a little more specific at +/- 3/4 inch size. You can use any size and type of gravel you wish for a French drain, but septic systems benefit from crushed gravel of this size for greater surface area for optimal treatment of waste effluent. 

Some engineers go one step further and lay 2 inch diameter perforated pressurized distribution pipe in the top of chambers with 1/4 inch diameter holes every 2 foot facing upwards to ensure equal effluent introduction throughout the trench. This only works with a lift station 'dosing tank' to send a couple hundred gallons of effluent out at one time. Non-pressurized (no pump or dosing tank) systems do not benefit from distribution pipe since the larger 1/2 inch diameter holes must face downwards and effluent rarely reaches the end. When specified, non-pressurized systems strap 4 inch perforated pipe either side of the structural columns found on Quick4 Plus chambers. Do not run distribution pipe along the base of the trench since that area can be flooded at times should percolation rate be slow. Several inches of gravel atop chambers with a layer of geotextile fabric on top and sides is common practice in sandy or silty soils. Best practice is to limit trench lengths to about 50 foot (12 to 13 four foot long chambers) for full trench saturation and best treatment of effluent.

Always vent the ends of each chamber run to ensure healthy air flow through system. Inspection port at end of each run must be drilled with holes to provide venting. Air is pulled through the chambers and out the plumbing vent atop roof of house. Fresh air and healthy soil are critical for long-term viability of leach fields. Standard ventilation specification is 1/8" diameter holes drilled at least one every square inch for at least eight inches above finish grade and capped. Larger holes are discouraged to prevent insects from nesting in the vent port. By allowing air to draft through chambers, you provide oxygen to an otherwise sealed cavity. Encouraging aerobic (oxygen-based) bacteria to prosper inside the leach field helps keep soil healthy and limits the growth of bio-mat anaerobic (no-oxygen) build-up from septic effluent particulates. Bio-mat formation is what eventually clogs soil, stops percolation, and causes leach fields to fail.

Take with a grain of salt, any claims of "superior" systems such as the Eljen GSF 'geotextile sand filter' with passive advanced treatment technology. In our experience, clients very rarely concern themselves with more effective treatment of wastewater, but rather the ultimate longevity of their leach field. Chamber systems have the major advantage of a very large surge volume, something niche systems like the Eljen GSF geotextile sand filter do not offer. In the long run, having a larger retention area for daily surge potential is what keeps a leach field from failing, not shiny bells and whistles. We recommend installing the largest septic tank possible for optimal settling and filtration before wastewater reaches the leach field rather than investing in wastewater treatment gimmicks. We cannot recommend Easy Flow 'engineered drain systems' which combine corrugated slotted pipe wrapped with geotextile fabric and expanded polystyrene aggregate (packing peanuts) held in place with a netting wrap. These are fine for a French drain, but not when used in a septic system leach field. Easy Flow longevity is terrible given the accumulation of bio-mat inside the pipe and against the geofabric wrapping. They are an absolute nightmare should the contaminated pipe and packing peanuts ever have to be removed. Worst job ever.

never use ANY additives or enzyme digesters

Properly sized two compartment septic tanks operate just fine without potentially dangerous additives. Breaking down fats and solids in the septic tank with digestive enzymes simply allows these now much smaller particles to pass through the septic filter where they reunite in the leach field, forming a dense bio-mat. The FDA has never approved any additives; none are considered safe or effective. You don't want these additives finding their way into the groundwater where they can be used for irrigation and drinking. Leach field distance from the wellhead (100 to 200 feet) is no guarantee of safety, it's just an arbitrary number locally assigned to allow residential construction on smaller half acre lots. Lateral water (sewage effluent) movement underground is extremely unpredictable at certain times of the year and will easily contaminate your well. Any chemical (or enzyme) which digests sewage should frighten a reasonable person to allow in their drinking or irrigation water.

bed all leach field pipe in plenty of gravel

All pipes must be well-bedded in at least six inches of +/- 3/4 inch gravel to avoid frost issues or soil settling and heaving pipe off-level. Best practice is first connection (joint) at effluent pipe coming out of foundation be made with rubber boot coupler. Common mistake is solvent welding that first joint with a hard fitting and not bedding pipe. Should the newly installed pipe run settle, a rubber boot coupler will adapt, unlike solvent welded joint. Pipe from foundation to septic tank slopes maximum of 1/4 inch per foot. Too steep of slope and water will bypass solid waste in the pipe, eventually clogging it. Slope minimum 1/8 inch per foot from septic tank to distribution box and leach field. Much steeper is possible, but best to level-off prior to the distribution box or the turbidity will affect equal splitting to runs. Use lots of purple primer on all pipe joints and splash it around to allow inspector to clearly see everything was properly primed before solvent welding.

Four inch diameter sewer pipe comes directly from cleanout, immediately adjacent foundation, to the septic tank. No bends should be installed between house and septic tank or toilet waste may settle in the line and eventually block flow. After the septic tank, sewer pipe can make bends as need be. Just maintain 1/8 to 1/4 inch per foot slope until the septic tank. Greater slope than 1/4 inch per foot may allow water to flow around toilet waste, allowing it to settle and block flow. Less than 1/8 inch drop per foot and you may leave flat sections or dips that can freeze. When designing site plan, you are not limited to coming in one end of tank and out the opposite end. Infiltrator tanks can be plumbed from three directions on both ends. 

Critical detail is to bed all pipe, fittings, and distribution boxes well in at least six inches of gravel to ensure level is maintained and frost is not an issue. Best practice is to 'wet-set' distribution box atop a bag or three of Quikrete to ensure level is maintained. Wet-set refers to pouring dry concrete mix under and around and then wetting it with water. You can pre-mix the concrete or set with minimal water in the field with 'fence post' dry mix. Fill the bottom of D-box with water up to hole openings to give it some weight. Water will exit all outlet holes evenly when box is perfectly level. Bringing lid up to near the surface with D-Box risers will allow use of Speed Levelers to dial-in accurate distribution. Rotating speed levelers upside down allows individual runs to go fallow and dry out seasonally to help protect longevity.

Concerning the use of Sch40, SDR35, or ASTM 3034 pipe in septic systems, SDR35 'sewer, drain, vent' pipe with 3034 fittings is adequate for wastewater systems outside the home foundation.  Sch40 thick wall pipe is only required for pressurized water systems. Sch40 might help should you ever drive over the system, but one should never ever drive over any pipe. At the very least, you may create a dip in the line and block flow. Should you be forced to drive over a section of pipe, always 'sleeve' the four inch pipe inside an outer six inch Sch40, or thicker, galvanized metal pipe.

steep slope leach field design & installation

To be properly engineered, steep slope installations require a professional soil survey and groundwater impact study. While there is plenty of literature online, the list of specific site variables is virtually endless, so you run the risk of not asking the right question(s). For instance, soil erosion may be a critical issue never considered. In practice, effluent needs to percolate vertically through at least three feet of amenable soil before it enters the groundwater. This level of sewage filtration is considered the bare minimum acceptable in most of the country. Sand mounds and advanced treatment systems are commonly specified when either the soil is not amenable or the site is too steep. Local building codes always dictate.

The main concern on a steep slope is preventing effluent from traveling laterally down the hill, either above or just beneath the surface. In a worst case scenario, effluent is unable to percolate vertically, for proper waste treatment, and ends up becoming surface runoff, flowing directly into an adjacent waterway. The bottom of any slope is by definition a 'seasonal waterway' during periods of heavy rain or spring snow melt. Be very aware of neighbors' well head locations.

Physically, you start by excavating 'benches' (terraces) that are level from one end to the other. Then, soil allowing, you cut your three foot wide trenches (standard Quick4) contouring them to the hillside. Key is having a level trench to install chambers. Quick4 can be curved to adapt to a contured hillside, so the trenches do not have to be straight, just level. You often end up with a design that benefits from 'center feeding', which is bringing effluent into the middle of a run, not the end. Here is an introductory article from Infiltrator's Onsite Installer magazine with some handy illustrations.

Engineers seldom consider the aesthetics of a steep slope layout. Given overall dimensions, these terraces are a commanding landscape focus. You can create wet-sand scale models to test alternatives. Talented survey crew, solid geometry, and quality woven geofabric are keys. Expanding the overall width/depth of your 'benches' will greatly increase terrace square footage with minimal machine time. Plus, wider benches provide safer perches for your excavator.

"Are we allowed to install this septic system on our property" or "how many chambers do we need" are not questions we can answer for you. We have been providing septic system parts for over thirty years now, but we do not follow constantly changing city, county, and state building regulations. Unfortunately, with over 3000 counties in the United States, regulations changing from year-to-year, and interpretations of those rules varying from one inspector to another (and one engineer to the next), it's never possible to be certain 'what is allowed' locally. We encourage clients to mail copies of their septic system plans for our free review with purchase of a system. But understand that The Natural Home is not an engineering firm; we do not provide any engineering services, soil testing or on-site work.