Lesson Notes By Weeks and Term - Junior Secondary School 2







  • MELROSE, Basic Science and Technology Book 2
  • NERDC, Basic Technology for JSS, Book 2





  • Definition of Tap
  • Types of Taps 
  • Water Supply/ Plumbing/Fitting   


Definition of Tap

A tap is a valve controlling the release of a liquid or gas. Taps are made using a wide range of materials, including stainless steel, chrome, brass, nickel and gold.


Types of Taps

They are three main varieties of washerless tap available nowadays these are

  1. Ball taps: This work by pushing a hollow plastic or stainless steel ball over a rounded cover, which controls the temperature and flow of water.
  2. Cartridge Taps: These have a lever controlling a plastic or brass cartridge which moves up and down to restrict flow and from left to right to change temperature.
  3. Ceramic disc Taps: This have two ceramic plates which slide over each other to regulate temperature and flow and require the least maintenance out of all the types.


Tap Styles

  1. Cross head tap
  2. Lever tap


How Taps Work 

Different taps also regulate the water in different ways. Many of us are familiar with the compression type of tap – when the tap is screwed down it compresses a washer made of rubber or neoprene against a metal seat, which restricts and water flow. These washers will wear out over time, and need to be replaced 


Water Supply/Plumbing 

Definition of plumbing

Plumbing can be defined as the system of arranging and connecting pipes with others things (fittings and machines) that supply water to and drain liquids wastes out of the building. 

Domestic pipeline fitting has the following components

    1. Stops Corks
    2. Drain Corks
    3. Valves (gates valves bul-valves)
    4. Taps 
    5. Elbows
    6. Tees 


  • Stop Cork: This is used to control the flow of water through water supply pipes.
  • The Stop Cork has a crutch handle, which is turned clockwise or anticlockwise to raise or lower the jumper on valve seating.
  • Drain Cork: It is connected to a water supply pipe in order to drain off water.
  • Gate valve: It is a valve that is used in controlling the flow of water in the distribution pipes.
  • Taps: We get supply by opening a tap at the end of the supply line.
  • Elbows: These are connected to the water supply pipe to change the direction of flow through an angle. For example, it is important when a horizontal pipe is to be connected to a vertical pipe. One end of the elbow turns through the required angle (90, 112½ , 135 , 157½  )
  • Tee: A tee is used for joining three pipes meeting at a junction from one of the pipes the flow divides into the two other pipes.




  • Define (a) Tap    (b) Plumbing
  • State three (3)types of tap
  • Explain five (5) domestic line fitting and state their uses.




Pipes referred to as the mains are laid underground to distribute water to various outlets. The water from the street mains enters the compound of a building in a 30m-diameter pipe (community pipe). It connects to a side of the water authority stop cork which buried in a pit at least 80cm deep.


The main pipes are laid underground to distribute water to various outlets. The main is connected to the kitchen sink to outside tap and up to the elevated tank. Baths, water closet, washing hand basin and hot water system are supplied directly by gravity through a 22m diameter pipe from the overload storage tank.



Water storage tank is important when one considers the fact that regular supply of water cannot be guaranteed. Storage tank is important because:

  1. The demand for water varies during the day from the peak period demand in the morning to low demand later in the evening.
  2. Water is distribute from the storage tank generally at low pressure, thus if there is a leakage along the supply line, It will not as serious as leakage along the high-pressure supply mains.
  3. There are occasions when the water authority has to cut off supply to effect repairs unless one has a storage tank there will be no supply to the building.



They are made from stainless steel or enameled steel. Sinks are provided with piller bib taps depending on the orientation of water supply pipe. It has over flown hole to provide passage for water in case of the tap being carelessly left open. A’s tipper is used to block the water passage when the tap is open to provide a pool of water for washing. 

When blockage occurs, a sink plunger down or a force cup may be used. The plunger placed over the waste outlet is then plunged down forcibly as many times as necessary. 

The plunging action generates a lot of compressive force, which moves the obstruction out of the way. If the plunging fails to remove the blockage the clearing “ey” will have to be unscrewed. A wire can then be used to probe into the piping to dislodge the offending materials.



Wash basins are usually made of ceramic. It has almost the same component as the sinks.



Baths are of different sizes and shapes. They are made of enameled cast iron or acrylic plastic. Cold water taps as well as hot water tap is provided. It also has a stopper to stop water flow as often required.


For a body wash, there is a great advantage in installing a shower:

  1. It ensures economical use of water than a bath tub.
  2. Showers are more hygienic.



The water closet is one of the most important components of a household’s plumbing installation.


Human wastes are got rid of through the W.C. Any malfunctioning will lead to an unhealthy environment. The cisterns contain at least two gallons of water.  



Hot water system is required mainly for providing warm water for bathing and for brushing the teeth at washbasin. This can be achieved. This can be achieved by installing an electric water heating system. The hot water is piped to the bathtub and washbasin.



  1. Define (a) Taps (b) Sinks (c) Basins
  2. State the types of taps we have



The importance of drainage cannot be over-emphasized. A drainage system must be provided with a pipe to get rid of liquid waste from kitchen sink, the bathtub, and the wash hand basins, water closets.


The effluents flushed from the W.C travel through the ‘soil’ pipe into the inspection chamber, which constituted the junction for all drains. The water drained from the water basins travel through a separate pipe first into a gulley where in solids are removed before the drain enters into the inspection chamber, 


After the inspection chamber, the liquid waste either goes into the public sewage works or a septic tank. The septic tank is an underground chamber into which sewage from the house enters and leaves as clean effluent. The inlet of the septic tank is slightly higher than the outlet, this is to ensure that when fresh discharge of sewage enters the tank, an equal volume of old liquid in the tank is displaced into the filter tank, anaerobic bacteria (bacteria which cannot live in the pressure of free oxygen) act on the sewage to break down the solids to liquid, gas and mineral sludge.

The liquid effluent from the tank enters the second chamber or filter tank where aerobic bacteria (bacteria which live in the presence of oxygen) complete the sewage purification process by oxidation. 


For septic tank to be able to perform the above-mentioned point, than these practice should be noted.

  1. The use of disinfectants destroyed the disease germs in a toilet and at the same time destroy the bacteria in the septic tank, thus it slows down the bacterial action in the waste.
  2. Household chemicals like bleaches, detergents etc when used excessively and sent into the septic tank interfere with the bacteria decomposition of waste. The rate of absorption of the soil is thereby reduced liquid effluent from the soil may then find its way to the surface consequence the surrounding area get polluted.
  3. The empty of large volume of water may result in the churning up of the solids that are still being broken down by bacterial action as well as the sludge. Such products may also flow into the filter or drainage field to cause clogging 
  4. It is important to establish the absorption properties of soil in an area where septic tank is to be installed.



  1. Explain the following 
  • sink
  • water closet
  • storage tank
  1. Mention three practices to be noted in the use of septic tank in our home.



Read more on taps and water supply 



  1. The system of arranging and connecting pipes with others things (fittings and machines) that supply water to and drain liquids wastes out of the building is called___ (a) plumbing (b) bricklaying (c) rendering (d) setting out
  2. The following are components of domestic pipeline fitting has the following except (a) Drain Corks (b) Valves (gates valves bul-valves) (c) Elbows (d) bore hole
  3. Which of the following is used to control the flow of water through water supply pipes? (a) Drain Cork (b) Stop cork (c) Elbow(d) bore hole
  4. Which of the following is used to get rid of human wastes? (a) the Water Closet  (b) bath hub (c) storage tank (d) sink
  5. The system that is used to get rid of liquid waste from kitchen sink, the bathtub, the wash hand basins and water closets is called___ (a) A drainage system (b) liquid system (c) power system (d) cleaning system


  1. Define the following terms A. Plumbing B. Tap C. Sink
  2. Explain five (5) domestic line fitting and state their uses.

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