Storage tanks

Hey Future Master Plumbers! Let's Talk Tanks!

Habari zenu! Ever been in the middle of a nice shower when suddenly... *psssst*... the water is gone? Or your mum is in the kitchen and the tap runs dry? We've all been there! The council water supply can be unpredictable. But what if I told you there's a silent hero in most Kenyan homes, sitting on the roof or on a tower, making sure you have water even when the mains are off? Today, we're diving deep into the world of Cold Water Storage Tanks (or as we often call them, *tangi za maji*).

Think of a storage tank as a power bank for your water. It stores water when it's available, so you can use it whenever you need it. Let's get started!

Why Do We Even Need a Storage Tank?

You might think, "Why not just connect the pipes directly from the county council supply?" Well, a storage tank does more than just hold water. It's a crucial part of a safe and efficient plumbing system. Here are the main reasons:

• Acts as a Reserve: This is the most obvious one! In Kenya, water rationing or supply interruptions are common. A tank ensures your family has water for drinking, cooking, and cleaning for at least a day or two.
• Breaks Pressure from the Mains: Water coming from the main supply line can have very high pressure. This pressure can damage your taps, toilet flushing mechanisms, and pipe joints. A tank "breaks" this pressure by taking in the high-pressure water and releasing it into your house pipes using gentle, reliable gravity.
• Provides a Steady Supply for Other Systems: It provides a constant and steady head of pressure to feed other systems, especially the hot water cylinder (geyser). Most geysers are not designed to handle high pressure directly from the mains.
• Emergency Use: In case of a fire or other emergencies, the stored water can be a lifesaver.

Real-World Story: I once got a call from a frantic homeowner in Buruburu. His new shower head had blown right off the wall! The problem? His plumber had connected the shower directly to the high-pressure mains supply, bypassing the storage tank. A simple storage tank would have prevented that expensive and watery mess!

Types of Storage Tanks: The Famous, The Strong, and The Hidden

When you look at the rooftops in any Kenyan town, you see a variety of tanks. They are mostly classified by the material they are made from.

Image Suggestion: [A vibrant, detailed photograph of a typical Kenyan urban skyline (e.g., Nairobi or Mombasa) at sunset. The focus is on the rooftops, which are crowded with various types of water storage tanks. Prominently feature a green Roto plastic tank, an older silver galvanized steel tank, and a few others in different shapes and sizes. The lighting should be warm, highlighting the texture and form of the tanks.]

• Plastic (Polyethylene) Tanks: These are the most common ones you see everywhere, often from brands like Roto or Kentank. They are popular because they are lightweight, relatively cheap, and don't rust. Their main enemy is the sun's UV rays, which can make them brittle over many years.
• Galvanized Iron (G.I.) Steel Tanks: These are the old-school, tough guys. They are very strong and durable but are also heavy and can rust over time if the protective zinc coating gets damaged.
• Glass Reinforced Plastic (GRP) / Fibreglass Tanks: These are very strong and resistant to corrosion. You often find them in larger buildings like hospitals, schools, or factories because they can be made in huge rectangular panels and assembled on-site.
• Concrete Tanks: These are often built underground and are used for very large-scale storage, like for an entire estate or institution. They are permanent and very durable.

The Anatomy of a Storage Tank System

A storage tank isn't just the tank itself; it's a whole system with several important parts. Let's look at a typical setup. Understanding this is KEY to your job!

      +-----------------------------------------+
      |                Tank Lid                 |
      +-----------------------------------------+
      |                                         | ----> Overflow Pipe (Safety)
      |                                         |
      |   (Water Level) ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~   |
      |               /                         |
Inlet -----> Float Valve                        |
Pipe      |                                         |
from      |                                         |
Mains     |                                         |
      |          COLD WATER STORAGE           |
      |                                         |
      +-----------------------------------------+
                    |           |
                    |           |
       Outlet Pipe (to house)   Scour/Drain Pipe (for cleaning)
                    |           |
                    V           V

• Inlet Pipe: This pipe brings water from the main county supply into the tank.
• Float Valve (Ball Valve): This is the clever gatekeeper. As the water level rises, a float (the ball) rises with it and slowly closes the valve, stopping the water when the tank is full. It prevents wastage and flooding. It's the same principle used in your toilet cistern.
• Outlet Pipe (Distribution Pipe): This pipe takes the stored water out of the tank and distributes it to the taps, toilets, and showers in the house. Note that it's placed slightly above the bottom of the tank to avoid drawing out any sediment or dirt that has settled.
• Overflow Pipe: This is your crucial safety net! If the float valve fails, this pipe will direct the excess water out of the tank to a safe, visible place (like onto the roof). This immediately tells you there is a problem. Rule of thumb: The overflow pipe must be wider than the inlet pipe.
• Scour or Washout Pipe: This is a drain located at the very bottom of the tank, used for emptying it completely for cleaning and maintenance.
• Lid/Cover: A tight-fitting lid is non-negotiable! It keeps out dirt, leaves, insects (especially mosquitoes!), and animals, ensuring the water stays clean and safe.

The Big Question: How to Size a Tank? (Let's Do the Math!)

A client will ask you, "What size of tank do I need?" Your answer will show if you are a true professional. You need to calculate the household's water demand.

A common estimate for domestic use in Kenya is about 150 litres per person per day. We usually want to store enough water for at least 24 hours (1 day).

Scenario: You are installing a water system for a family of 6 people in Kiambu. You need to recommend a tank size.

Step 1: Calculate the Total Daily Demand

   Number of people x Litres per person per day = Total Daily Demand
   6 people x 150 Litres/person = 900 Litres

Step 2: Add a Safety Reserve (optional but recommended)

   It's wise to add a small reserve, say 20%, for unexpected needs or longer water outages.
   Reserve = 20% of 900 Litres
   Reserve = 0.20 * 900 = 180 Litres

Step 3: Calculate the Total Required Storage

   Total Daily Demand + Reserve = Total Required Storage
   900 Litres + 180 Litres = 1080 Litres

Step 4: Choose a Standard Tank Size

   Tanks are sold in standard sizes (e.g., 500L, 1000L, 1500L, 2000L, 5000L). You can't buy a 1080L tank.
   You must choose the next size UP.
   
   Therefore, the most suitable standard tank would be 1500 Litres. A 1000L tank would be too small.

   Final Recommendation: A 1500-Litre Tank.

Installation: Do It Right, or Do It Twice!

A great tank installed poorly is a disaster waiting to happen. Remember that 1000 litres of water weighs 1000 kilograms (1 Tonne)! The support structure is critical.

• The Foundation: The tank MUST be placed on a completely flat, level, and solid base. For ground-level tanks, this is a concrete slab (plinth). For elevated tanks, it's a strong, well-built steel or concrete tower. The base must support the entire bottom of the tank.
• Location: Ensure there is enough space around the tank for future inspection and maintenance of the pipework.
• Connections: Use high-quality fittings and thread seal tape (PTFE tape) to ensure all connections are leak-proof.
• Support the Pipes: Make sure the pipes connected to the tank are properly supported with clips so they don't put any strain on the tank fittings.

And that's a wrap on storage tanks! From understanding why we need them to calculating the right size, you now have the foundational knowledge. This is one of the most common jobs you will do, so master it! A well-installed tank means a happy client with a reliable water supply. You are not just a plumber; you are providing an essential service to families and communities. Keep up the great work!