Plumbing & Septic Systems


All About Septic Systems

Septic systems are a "dirty" topic, but one that should at least be understood by homeowners. Here's an overview of how your septic system operates as well as preventative maintenance steps you can implement.

The Way A Typical Residential System Works

  1. The waste from the house goes into the tank and the anaerobiotic bacteria breaks down approximately 65% to 70% of the solid waste.
    NOTE: Anaerobiotic bacteria develop when air is not present (Most common type system). Aerobic bacteria develop in the presence of air and would break down 90% to 95% of the solid waste. This can be done with a small air compressor.
  2. The liquid waste is called effluent and normally goes into the leaching fields at the same rate that you use the system. Example: If five gallons of waste goes into the tank (liquids and solids), five gallons of effluent goes into the leaching fields.
  3. The effluent goes into a distribution box that is installed level so that each leaching bed receives the same amount of effluent.
  4. When the effluent goes into the leaching fields it is absorbed by the soil.

The Parts of a Septic System

Concrete or steel tank (1,000 gallon is typical)

  1. With maintenance, a concrete tank will typically last 40 to 50 years.
  2. Steel tanks typically last 20 to 30 years. (Note: These were last installed in the middle 1960s.)
  3. The tank has inlet and outlet pipes and baffles to separate scum/grease from the effluent that goes into the leaching fields.

Leaching fields

  1. Stone beds with a perforated pie (in most cases)
  2. Sand mounds are only needed if the soil does not "perk". (See "perk" explanation below.)

Maintenance Suggestions

  1. A septic tank should be pumped out every 24 to 36 months (average family of four people).
  2. A clean out should be installed if there is none.

Other Information

  1. Do not use a garbage disposal when you have a septic system or cess pool because it will dilute the biological farm (deplete bacteria activity). Note: Photographic chemicals that are disposed into the system will tend to shorten the life of the septic system.
  2. "Perkability" is the rate at which the soil will absorb water. Check with the local authorities for the acceptable rate. You should test about eight times or until the readings become stable. Note: Perkability tests are performed before a system can be installed.
  3. The tighter the soil is, the shorter the life of the leaching fields and the less the soil will "perk".
  4. Leaching fields are not to be below 3'.
  5. Cost for a new septic system is approximately $5,000 to $10,000, depending on the conditions. An elevated sand mound could be an additional $3,000 to $5,000.
  6. Adding yeast to a septic tank to help the bacteria activity is a myth. Human waste will produce ample amounts of anaerobiotic bacteria.

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Solving Sewer Odor

Sewer odor that comes from either a plumbing fixture or an open drain pipe make your living space an unpleasant place to be. And, unfortunately, problems like this may be difficult to solve.

Every fixture in your drainage system should be protected from sewer gas back-up by a water trap. You can see the "P" traps under sinks and tubs. Water sits in the lower part of the "P" bend and the odors cannot back up into the house. Traps in toilets are built into the base and are invisible, but the water you see in the bowl is part of the trap system.

Water traps are quite effective in sealing sewer odors while still allowing water and waste to pass to the sewage system. However, if another part of the drainage system is defective (i.e. venting or traps that dry out or siphon) the water traps can be defeated and gases can enter the house.

Vents are connected to the drainage pipes and allow air to enter the system. You need venting to prevent water from being sucked from the traps when, for instance, a toilet is flushed in the upper part of the house. The falling slug of water and waste from upstairs could create a vacuum on its way down that would remove the water from a vanity or kitchen sink trap if the vent is blocked or not present. 

So, you’ll have a venting or trap problem somewhere in your drainage system. If the odor occurs only when the toilet is flushed in a downstairs bathroom, the waste discharge may be forcing some sewer gas out a drain pipe somewhere. Proper venting will allow the gases to go out of the vent that penetrates the roof.

However, the problem may not be that at all. There might merely be a drain without a water trap in the basement somewhere. Check the laundry area and washing machine standpipe. I’ve seen several that did not have a trap. Sewer gas can enter the house through such an untrapped drain.

Also check the basement floor drain. If there is one that rarely if ever gets used, it is possible that the water in its trap has evaporated. Pour a pint or so of water into a floor drain to replenish the trap and re-establish the seal.

One can test both a standpipe and floor drain for sewer gas entry by laying a piece of tissue or other lightweight paper over the opening. Have someone flush the downstairs toilet and watch to see if the paper moves. If it does, the problem area has been identified. 

Do not test for this air movement by using a lit match or lighter! Sewer gas contains methane, a flammable gas, that could ignite. This, by the way, and the fact that sewer gas contains bacteria, is a very good reason to get to the bottom of this problem and eliminate it. 

If a floor drain and laundry standpipe check out, there might be a defective vent or drain pipe hidden in the walls somewhere. However, unless the house is quite old, this scenario is unlikely. Cast iron waste and vent pipes have long lives, however, failures typically develop in 60 to 100 years.

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Faucets and Showers

Simply repairing leaks in faucets and showers can save hot water. A leak of one drip per second can cost $1 per month, yet could be repaired in a few minutes for less than that. And some apparently insignificant steps, when practiced routinely at your household, could have significant results. For example, turning the hot-water faucet off while shaving or brushing your teeth, as opposed to letting the water run, can also reduce water-heating costs. Another option is limiting the amount of time you spend in the shower.

Other actions may require a small investment of time and money. Installing low-flow shower heads and faucet aerators can save significant amounts of hot water. Low-flow shower heads can reduce hot-water consumption for bathing by 30%, yet still provide a strong, invigorating spray. Faucet aerators, when applied in commercial and multi-family buildings where water is constantly circulated, can also reduce water-heating energy consumption. 

Older shower heads deliver 4 to 5 gallons (15.1 to 18.9 liters) of water per minute. However, the Energy Policy Act of 1992 sets maximum water flow rates at 2.5 gallons (9.5 liters) per minute at a standard residential water pressure of 80 pounds per square inch (552 kilopascals).

A quick test can help you determine if your shower is a good candidate for a showered replacement. Turn on the shower to the normal pressure you use, hold a bucket that has been marked in gallon increments under the spray, and time how many seconds it takes to fill the bucket to the 1-gallon (3.8-liter) mark. If it takes less than 20 seconds, you could benefit from a low-flow showered. A top-quality, low-flow showered will cost $10 to $20 and pay for itself in energy saved within 4 months. Lower quality shower heads may simply restrict water flow, which often results in poor performance.

Because of the different uses of bathroom and kitchen faucets, you may need to have different water flow rates in each location. For bathroom faucets, aerators that deliver 0.5 to 1 gallon (1.9 to 3.8 liters) of water per minute may be sufficient. Kitchen faucets may require a higher flow rate of 2 to 4 gallons (7.6 to 15.1 liters) per minute if you regularly fill the sink for washing dishes. On the other hand, if you tend to let the water run when washing dishes, the lower flow rate of 0.5 to 1 gallon per minute may be more appropriate. Some aerators come with shut-off valves that allow you to stop the flow of water without affecting the temperature.

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Does Your Water Heater "Percolate?"

Your coffee maker may not be the only thing in your home that percolates. It’s not uncommon to find hot water heaters percolating due to "hard" water.

Ground water picks up minerals from the earth as it flows through layers of rock and soil. These minerals remain suspended in the water until they come to rest or are heated, as they are in your water heater.

At that point, they begin to precipitate out and begin to bond with each other and cling to whatever vessel holds the water. Over time, the building-up of these minerals in a water heater can reach astonishing proportions -- ask anyone who has ever had to lug a limed-up old water heater out of a house.

Even though you may have faithfully drained your water heater now and then, the minerals keep coming in with new water and, unfortunately, they can’t all be drained before they begin to build up. Also unfortunately, these minerals form a blanket of insulation between the bottom of the water heater and the rest of the tank.

It is this layer of minerals that is the likely cause of the noises one hears. As the thermostat calls for the burner to fire, assuming it’s a gas water heater, the flame heats the bottom of the water heater tank. The tank, in turn, heats the water directly above it. The minerals insulate the heat from the water and causes the popping.

It’s easy for the flame to overheat this water. The tank can also overheat, stressing the metal and causing it to expand excessively. These two activities account for the water heater sounding like a "giant percolator."

The insulating blanket of minerals is more than just acoustically annoying. The constant overheating of the metal tank bottom contributes to metal fatigue. In addition, most steel tanks are lined with a thin layer of glass to prevent rusting. Constant over-expansion of the tank can crack the glass, leading to premature failure. The mineral layer also keeps heat from reaching the water in the tank above, resulting in higher gas bills.

What can be done about the problem? There are two options: 1) Replace the water heater, or 2) clean out some of the minerals. If the homeowner is an agile and patient worker, he or she can remove most of the minerals in the water heater. This can be done by draining the heater and accessing the inside through the drain valve.

This is not a job for the faint of heart. It involves crouching in a kneeling position for an extended period, requires some basic tool-handling skills, and generally makes a big mess. 

To begin, turn off the gas and the water. Drain the tank using a hose. It helps to open a hot water faucet at a fixture above the tank to let air into the system.

With the tank empty, remove the drain valve from the water heater. Look inside the tank with a flashlight. You will see some water at the drain level, and probably a large, crystal-like chunk of white mineral growth.

You will get the minerals out of the drain opening by breaking them up and sucking them out with a modified wet or dry vacuum. Cut a sturdy coat hanger and form a hook on one end. Plunge the hooked end into the mass and ream it around, breaking off manageable chunks.

Next, tape a short length of flexible plastic tubing, the outer diameter of which should just fit into the drain opening to the hose of the vacuum and push it into the drain hole. Turn on the vacuum and evacuate what you’ve broken up, along with some of the water.

Periodic shots of water may have to be added to the tank (open the shut-off valve briefly) to suspend some of the solids so the vacuum can suck them up. Repeat these steps about a thousand times and then get up off your knees and take some aspirin.

You can chuck the coat hanger in a cordless drill to provide a bit more reaming power, but you must be very careful not to damage the tank’s lining. When you finish, replace the drain valve, fill the tank (keep the faucet open while you do this to give the air a place to go), turn the gas back on, and relight the pilot.

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Inspecting Your Plumbing

A professional home inspector determines the condition of a home by looking for "signs" that tell a story. These signs may indicate that a problem exists. Thanks to a thorough understanding of the signs, inspecting homes is fast becoming an exacting profession. There are hundreds of signs professional home inspectors use that can help you uncover the basic condition of a home. Once these conditions are understood and problems that exist are uncovered, you can plan a strategy for repairs or replacement.

Here are the signs to look for when inspecting a plumbing system.

Water Supply Piping

  1. Copper water piping is a dependable material; however, wells with acidic water can cause the copper piping to fail. Look for pinholes in the piping. They will be marked by small greenish rings.
  2. Steel water piping has a life expectancy of 40 to 70 years, depending on usage and the local water. Oxidation or rust develops from the inside of the pipe. Initial failure is evidenced by rust spots which appear to be rust growths on the outside of the pipe.
  3. Plastic water piping is not used in most areas of the country and has had problems at the joints, especially on the hot water lines. Newer chemical bonding causes the plastic pipe and fittings to fuse together and appears to have corrected the joint problems.

Drain Piping

  1. Cast iron piping is dependable for 50 to 90 years. Generally, the first failure appears as a crack on the top of the pipe approximately 8' to 20' below or past a vertical stack.
  2. Steel drain piping is dependable for 50 to 100 years. Rust develops from the inside and spots or growths appear on the exterior and indicate failure.
  3. Copper drain piping is very dependable. Failures are usually workmanship related.
  4. Lead drain piping is usually dependable for 60 to 100 years. This piping is relatively soft and hot water may cause it to sag and develop problems if not properly supported.

Vents, Fixtures, and Pressure

  1. Gurgling or air sounds indicate venting problems. Depending on the geographic location, vertical vents are required 5' to 12' from toilets.
  2. Gently rock toilets and sinks to determine if they are secure.
  3. Sink traps or piping which have been taped or caulked indicate that leaking has occurred. Tape and caulk are considered temporary repairs at best.
  4. Evaluate water pressure by operating the three fixtures in the highest bathroom. Open the tub spout because it does not have a screen or flow restrictor, flush the toilet, and open the sink faucets. If the pressure in the sink is acceptable, the house pressure is acceptable. Check the shower head separately because it has a flow restrictor.

Gas-Fired Water Heater

  1. Water stains below the tank or in the burner compartment indicate a possible failure.
  2. Burned paint on the cabinet indicates a problem in the burner compartment. The burner is not positioned correctly or the flame shield has failed. This is a fire hazard.
  3. Excessive rust in the burner compartment and at the gas bonnet (top of the unit) indicates there is a possible drafting problem.
  4. Thermally fatigued and distorted baffles indicate excessive wear and little or no remaining life. Use a mirror and flashlight to view the exhaust vent from the bottom of the unit.


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