Step 4d – Finishing the Septic Install

Well, as you can see, the entire septic system has been completed and covered with backfill.  The final steps involved building inspection ports from 6″ PVC and placing them over each of the ends of the drain lines. Each port has a plastic cap that can be lifted off to expose the 90 degree long sweep at the end of the line.  If for any reason the drain lines get clogged, you can take off the cap, reach down inside the PVC and unscrew the plug for the line in order to flush it out. Here you can see the end of one of the lines and the 90 degree sweep as it starts to curve up into the 6″ PVC.  The rebar going through the side of the PVC helps to support the drain line and to anchor the inspection port down in the dirt so it doesn’t move around.  You can also see the end piece screwed onto the last of the black infiltrators that protect the drain lines and also help to distribute the effluent spray evenly across the soil.  Towards the end of the day the backhoe operator returned and expertly returned the soil over everything and drove back and forth to compact the soil.  Here are a couple nice pics that really showcase the before and after of the septic install.

 

 

Step 5 – Get a Building Permit

With the lot now officially fully improved, the next step is obtaining a building permit.  The county website had a nice and easy step by step instruction on how to go about working your way through the process.  The first step I completed a few weeks ago when I received my accepted Natural Resources Assessment.  The next step is to make a prescreening appointment with the county building office.  They will expect to review my construction documents, request any necessary changes and/or alterations, and address any concerns they have.  At that time I will go back to the drawing board and make any corrections they require before my final permit appointment, where I will present the updated construction documents and get them signed off by the inspector.  I’ve been working on the plans for months now, and am finally getting close to finishing them.  I’m quite sure that there will be some corrections requested, but I also don’t want to give the inspector a first impression that I don’t have a good grasp on what I’m doing.  Here is a sneak peek at what I have so far….

My goal is to complete the rest of my plans over the weekend and schedule my prescreening for Monday.  The only thing I have left to do is the details page (although it might need 2 pages).  It will take some time because much like the floor framing page above, there are lots of leaders (the arrows with explanations) and it takes time to scale the cross sections properly.

Step 4c – Ready For Another Inspection

And there you have it folks.  My $7000 high powered sprinkler system!  Hard to believe that underneath the plastic “infiltrators” you see in the background and 12 inches of soil, that spray is going to be the last step in safely disposing of my sewage.  Today, the septic designer brought over the last piece I needed, a “hose assembly”, and we hooked it up.  The hose assembly attaches to the pump at the bottom of the tank and makes three 90 degree turns before exiting the tank and going through the pipes I assembled a few days ago.  Now it was time to fill up the pump chamber with water and test the system.  It was necessary to fill up the chamber with water for two reasons. First, you never want to run any kind of water pump without water in it because air has much lower resistance than water and the motor will burn out without that resistance (so make sure you aren’t out of windshield wiper fluid!)  Second, the panel won’t operate the pump unless both the redundant off and pump on floats have been activated and I’m not too keen on climbing down into the tank and flipping them upside down by hand.  After ten minutes or so I had enough water in the tank to activate both floats and I turned on the power to the control panel.  The pump activated and we got the beautiful water show you see at the top of the post.  The septic designer called the inspector for an appointment tomorrow so I can replicate the display for him and he will sign off on it.  There will be a few more minor things to assemble once that is done but nothing I can’t get done by the end of tomorrow as long as the backhoe operator shows up.

Step 4b – Inside the Tank!

Today I almost completed the septic install but am waiting on a couple more parts.  For the second time already in my build I underestimated the amount of wire I needed and now I’m stuck with a couple pieces that are too short and need to return to the electrical store to get longer pieces.  An important part of working solo is knowing where your deficiencies are and I tend to cut things just a little too close due to not wanting to waste anything.  With wire, hopefully this will be the last time I underestimate the length I need!

I began the day by running 1.5″ PVC from the tank to the drain field.  I learned a lot from the mistakes I made running electrical conduit since the white PVC for the septic is assembled and glued the same way as the grey PVC for the electrical.  The end result was a well planned and perfectly aligned run.  The next step was attaching the float switches inside the pump chamber of the septic tank.  There are three floats that will work together to operate the pump.  The float switches are bell shaped plastic parts attached to low voltage cords.  They are very simple but ingeniously designed.  When the water is low, gravity pulls the float down so the heavier bell end is down.  When the water level raises, the bell end floats upward, causing a sliding metal part inside the float to meet another metal part in the middle and complete the circuit.  The design was very specific on the placement of the floats on the PVC pole.

You can’t see them very well in the pic at the top of the page, but if you follow the white PVC pole that extends from the top of the tank down to the bottom on the right side of the pic, you will see three black objects attached to the pole at different heights.  The first float was to be placed 13 inches from the bottom of the tank.  This switch controls the ‘redundant off’ function in the control panel.  Basically it ensures that the pump continues to run until the effluent level is low enough to lower the float.  Without it, the pump would wear out a lot quicker because it would run so often.  Imagine if you took out the garbage to the street every time you had a piece of trash!  It’s much more efficient to have a small container and only empty it when the container is full.

The second float is placed 20 inches from the bottom of the tank.  Once the effluent level is high enough to raise this float, the pump activates and continues to run until the “redundant off” float is lowered.  The third float is the high level switch, and is placed 35 inches from the bottom of the tank.  This activates an alarm and a siren if the float is raised, and will allow me sufficient time to figure out what is wrong and fix it before the effluent level gets so high that the tank is full.  As you can see in the photo, the floats have cords that I coiled up and then ran into a junction box on the left side of the pic.  Inside the box, I spliced the wires with another set of wires coming from the control panel.  By code, you must use special silicon wire nuts to splice them to protect against the corrosive sewer gases that will soon occupy the tank (this is most likely overkill because the junction box is air and watertight.  You can also see in the pic the green pump at the very bottom of the tank and the white rope that I can use to pull it up if I ever need to perform maintenance on it (much better than diving in)

You can see how I’ve mounted the control panel on a 2×6 pressure treated post and run wires through 3/4″ conduit from the panel down towards the pump chamber riser.  Tomorrow I will buy a rubber grommet to make a seal as I drill a hole through the side of the riser and run the conduit into the junction box.  The last step will be running some 12/2 UF cable from my temporary power pole underground to the control panel.  If you look carefully you can see the 1.25″ connector at the bottom of the control panel where another conduit will run into the panel with power.

The other part I will get tomorrow is the flexible hose assembly that will connect the pump to the 1.5″ PVC I talked about in the beginning of this post.  Once that is hooked up it’s just a matter of filling the tank with water and checking to ensure everything is working properly.  In 4 days, the inspector will come and check for himself that everything is functioning properly and then I will be able to connect my trailer sewer to the septic inlet and start using it!  The backhoe operator will return and cover everything back up with dirt so the tops of the inspection ports are just barely visible.

Step 4a – Dropping the Tank and Gravelless Chambers

An exciting day today as I started installing the septic system. The experienced backhoe operator I hired was able to dig the enormous 9’x15’hole to a depth of 77 inches in less than an hour. I would have liked to do it myself and I realize now after having seen it done that with the right person checking the depth for me I could have done it but it would have taken me at least 5 times as long. The hardest part about digging a hole that deep is that you aren’t able to see the bottom of the hole from inside the cockpit of the excavator so you’re basically digging blind. Once the hole was dug I climbed down on a ladder and made sure it was nice and flat. We hit the water table around 6 feet down so I was working in about 6 inches or so of water. Once I was sure I had made a nice bed for the tank I climbed back out and we got started on digging the field. This part could have very easily been done by hand since the depth of the drain field is only 7 inches but since the excavator was already there it made quick work of the field. The field is 9’x35′ and must be flat and level so the first step is finding the lowest spot and digging down 7 inches from there. Once that is done it’s simply a matter of matching that depth to the remainder of the field. I used a 6 foot level and also a rotary laser level to check the depth, and a rake and shovel to fine tune things.

The pipes that disperse the effluent to the drain field are made from 2″ PVC that is reduced to 1.25″ PVC using 2 cross fittings and a tee fitting. You can see below how the 2″ pipe enters the field from the bottom right side of the picture and is attached to the 1st cross fitting underneath the black tunnel.  There will be another cross fitting underneath the 2nd tunnel and then a tee fitting under the last tunnel.  This allows the 2″ pipe to branch out into 6 different 1.25″ pipes and effectively disperse the effluent into the the field evenly.  The PVC is very simple to glue together with primer and cement.  Once they are glued, an 1/8″ hole must be drilled at the top of each 1.25″ pipe every 2′, starting 1′ from the place it tees off from the main 2″ pipe.  Those pipes are then covered with the large black gravelless chambers.  This allows the effluent to spray out of the small hole at the top and again, cover as much of the area of the entire field as possible.  The gravelless chambers are exactly what they sound like.  Instead of covering the PVC lines with gravel, you use the plastic chambers.  They are cheaper and much easier to install than shoveling gravel.  The chambers help direct the effluent sprayed from the pipes into the soil and also ensure that the pipes will be protected from human activity above.  Around this time the septic tank manufacturer arrived with the tank on the back of a flatbed.  The driver used a small crane on the back of the truck to hoist the massive tank into the air and carefully lower it into the hole we had prepared.  I had a hose all ready to start filling the tank with some water as soon as it was dropped.  This helps to give it some added weight and ensure it settles into the soil.  The backhoe operator also added soil around the sides but left the top and the inlet and outlet ports on the sides exposed.  He also graded the lot for me so as soon as I get my building permit I will be ready to paint some lines in the dirt to mark out the foundation.  In my next post I’ll add some pics of the inside of the tank as I connect the electrical panel to the pump and finish the installation of the septic system.

Step 4 – Septic System

Standard treatment of sewage hasn’t changed much over the years.  Nature actually had it figured out pretty good before humans even attempted to manage it.  Given enough time, soil and the organisms that inhabit it are extremely adept at breaking down harmful toxins and dispersing the safer compounds into underground waterways.  The only thing a septic system does is harness this awesome power.

Designing a proper system starts with a soils test and/or “perc” test.  A soils test involves removing a deep core of soil and analyzing what appears in the different layers.  Soil is then classified into sand, gravel, loam, clay, and all sorts of combinations of those types.  A perc test involves filling a hole with water and timing how long it takes water to percolate through the soil at the bottom of the hole.  Both tests can give a pretty good indication of how well a particular patch of soil will perform at breaking down the “effluent”, which is what sewage becomes after sitting for a period of time.

In my state, the soils test or perc test must be completed by a licensed septic designer.  The designer I hired charged $150 and found my soil to be “sandy loam” for the top inch and “medium sand” for the next two feet until reaching the water table at 28″.  This is the depth at which dry soil becomes saturated with water due to an underground spring.    The county and state health codes dictate what kind of dispersal system can be used for a given type of soil, and for my great soil and water table depth they allowed me to use a gravity distributed system, which is the simplest type.

The next step in the design called for locating the area of the lot where the drain field would be located.  Health codes dictate setbacks for the field of 5′ from property lines, 10′ from water lines, and 100′ from natural water supplies.  I have a natural canal on one end of my property, and the 100′ setback took up a substantial amount of the lot.  The drain field needed to be 400 square feet, and there also needed to be a reserve field of the same area set at least 6′ away from the main field.  I had a problem here because it was impossible to fit both fields into the setbacks.  Fortunately, by using the next system up from gravity I was able to use smaller fields that fit within the setbacks.

The type of design I will be installing is a pressure distributed system.  It’s basically the same as a gravity type system but with the addition of a pump.  This balances the distribution of effluent more evenly across the field and thus allows for a smaller area.  The sewage from the house exits the main drain pipe and enters a 3 compartment concrete septic tank.  The first compartment is aptly named the trash chamber, and allows the sewage to separate into solids on the bottom, a layer of sludge on the top, and a cleaner liquid in the middle.  This liquid is allowed to enter the second compartment, called the digestion chamber.  In order to exit this chamber, the sewage must decompose into small enough particles to pass through a filter.  In the last compartment, the clarifier chamber, the pump sits at the bottom.  When the level of liquid in the chamber causes a float to reach a certain height, the pump turns on and pumps some of the liquid out of the tank and through a pipe to the drain field.  There are two more floats, the first to ensure the pump doesn’t run too often and the second to sound an alarm if the pump isn’t working and the tank is getting full.  

It’s a relatively simple operation, so I’m planning to get it all done in less than a week!  In just two days from now, a local contractor with a backhoe will be coming out to dig a deep hole for the tank.  I will check the depth as he digs and ensure it is correct.  Around midday a crane will arrive and the tank manufacturer will drop it into the hole.  We will immediately begin filling it with water while the backhoe gets started on digging the main field.  It’s very important to get the drain field completely level and ensure that it is at precisely the correct depth.  If you go too low there won’t be enough soil to break down the effluent and you can’t just add soil back in because then it will be classified differently.  If you don’t go deep enough there won’t be enough soil to protect the effluent from the human activity above.  The health inspector must pass off the installation of the design and he will pay very close attention to the depth of the field.

In the few days following I will be assembling all the necessary pipes that lead to and from the tank, the floats that go inside the tank, and the pipes that will lie inside the field and distribute the effluent evenly across the entire area.  These lines will be covered with large plastic tunnels called gravelless chambers.  The last step will involve wiring the control panel to the floats and pump and hooking it up to power.  My goal will be to get it all done within 5 days because that is the day the health inspector comes out.  If I don’t finish I will have to wait another week!

I was very pleased with the deal that the septic designer got for me.  You can see the total cost of the system by clicking on the “Project Budget” link on the home page.  He is also going to check up on me throughout the installation to ensure I’m getting everything hooked up correctly.

Step 3b – Wiring and Inspection

Electrical wiring seems very complicated but its actually pretty simple.  The catch is that a mistake could possibly kill you.  Fortunately, when you are dealing with new construction, the power isn’t hooked up yet so you don’t have to worry about that.    The basics behind modern electricity can be pretty complicated, but here is a quick rundown.  Standard residential service uses alternating current with two 120 volt currents running in opposite phases.  Think of it like two pedals on a bicycle.  They are on opposite sides of each other but they can work together when you need them to.  Large appliances that need all 240 volts available can use a double breaker and take advantage of the added power.  Most normal circuits just utilize one phase or the other depending on where the breakers are situated in the panel.  As you can see in the photo at top, I have one 30 amp circuit powering the trailer using one phase and a 20 amp circuit for my tools on the other phase.  Within a couple weeks I hope to add two additional circuits on opposing phases to power my septic system.

As for the wiring of these circuits, the first step was to bring power from the utility company’s stubout to a meter socket.  The utility company will splice these wires to the ones they have in the stubout and put a meter in the meter socket so they can properly bill me for the power I use.  They are not allowed to complete these tasks until I have a sticker placed on my panel by the state electrical inspector.  In many states the building inspector does the electrical inspections but in Washington they are completed by the department of labor and industry.  According to the NEC (National Electric Code), you need to use size #4 copper or #2 aluminum wires to power a 100 amp service like the one I am installing.  Because these wires are run underground, they are required to be URD (underground residential distribution) conductors.  I used aluminum because it was cheaper.  Three wires are used, one for each phase of the AC current and one for the neutral wire where the power returns.  Think of electrical power like a river powering a water wheel.  If there is no place for the river to flow it won’t move and the wheel won’t move either.  Likewise, electricity won’t work unless it has a place to go and the neutral wire provides this path.

From the meter socket, the same URD wires are used to run the two “hots” and one neutral to the breaker panel.  Inside the panel, clamps are provided that connect to large metal plates for the “hot” wires, and a long metal bar for the neutral wire.  For every circuit, a breaker is connected to one of the metal plates and a white neutral wire is connected to the metal neutral bar.  The hot wire for the circuit is then connected to the breaker and the circuit is complete.  As you can see, I have one circuit to power the trailer that connects to a 30 amp breaker and one for my tools that connects to a 20 amp breaker.

There is a third wire on each circuit that is called the ground wire.  This wire is a relatively modern innovation for safety reasons and isn’t necessary to power either of the circuits.  Many elements have the ability to conduct electricity, including the human body, and electricity acts just as water does in that it will take the easiest path available.  A properly grounded electrical system provides a path with very little resistance so that, in the instance of a wire coming loose and briefly contacting a surface that conducts electricity, the surface charge will continue through the grounding system rather than remaining on the surface and electrocuting the next person that touches it.  The ground wires on the circuit are connected to a “grounding bar” inside the panel that is also connected through a copper wire to a 10 foot long copper rod that is buried all the way down into the earth.  Using our water analogy, this would be as if there was a water slide leading to a pool.  Some of the water might splash up onto the sides of the slide, but gravity is going to eventually draw it down into the pool.

So that basically covers the wiring of the system.  The hardest part is deciphering the NEC to figure out what type and size of wires to use.  There are many different kinds of conductors (THHN, THWN, XHHW, URD) which are basically single insulated wires, and then there are many different kinds of cables (UF, NM, SE, USE) which are several conductors independently insulated and bundled together and then given a second layer of insulation.  With the wiring completed, I was able to call an inspector in and he passed me off and put a yellow sticker on my service panel.  The utility company won’t connect the power without the sticker but now that I have it I can call them up and get connected.