How Portaloos Work: Quick Answer
🎯 Quick Answer
Portaloos work using a self-contained chemical waste system. Waste falls directly into a holding tank containing blue biocide chemicals that kill bacteria, break down matter, and neutralise odours. A separate fresh water tank supplies the hand wash basin. The entire unit is serviced weekly by professionals who empty the waste, refill chemicals, and sanitise the interior.
- Waste System: Chemical holding tank (200-250 litres)
- Odour Control: Biocide chemicals + ventilation
- Water Supply: Separate fresh water tank for hand washing
- Servicing: Weekly emptying and sanitisation
Continue reading for a detailed breakdown of each component and how they work together.
Ever wondered what happens when you use a portable toilet? Whether you’re managing a construction site, planning an outdoor event, or simply curious about sanitation technology, understanding how portaloos work can help you make better decisions about portable welfare facilities.
At Sitech Loos London, we’ve been providing portable toilet solutions across the South East for years. In this comprehensive guide, we’ll explain exactly how these essential facilities function—from the chemistry of odour control to the engineering of waste management.
👤 Written by: The Sitech London Technical Team Reviewed by: Operations Manager, Sitech Loos London Last updated: 19 January 2026
Table of Contents
- The Basic Anatomy of a Portaloo
- The Chemical Waste System Explained
- Ventilation and Odour Control
- The Hand Washing System
- How Portaloos Are Serviced
- Different Types of Portable Toilets
- Frequently Asked Questions
- Conclusion
The Basic Anatomy of a Portaloo
A standard portable toilet consists of several key components working together to provide a hygienic, odour-free experience:
1. The Outer Shell
Modern portaloos like the Satellite Maxim 3000 feature a double-skin HDPE (High-Density Polyethylene) construction. This UV-stabilised plastic is:
- Durable: Withstands impacts, weather extremes, and heavy use
- Easy to clean: Non-porous surface prevents bacterial buildup
- Lightweight yet strong: Enables transport while maintaining structural integrity
2. The Waste Holding Tank
Located beneath the toilet seat, this is the heart of the system. The tank typically holds 200-250 litres of waste and chemicals—enough for approximately 100 uses before servicing.
3. The Fresh Water Tank
A separate tank supplies clean water to the hand wash basin. This is completely isolated from the waste system to maintain hygiene standards.
4. The Ventilation System
Strategically placed vents draw air through the unit and up through a roof stack, pulling odours away from users and allowing fresh air to circulate.
The Chemical Waste System Explained
The chemical system is what makes portaloos work without mains drainage. Here’s how it functions:
The Blue Chemical Solution
When you look into a portable toilet, you’ll see blue liquid at the bottom. This isn’t just coloured water—it’s a carefully formulated biocide solution containing:
- Bactericides: Kill odour-producing bacteria
- Surfactants: Help break down waste and toilet paper
- Fragrance compounds: Mask any residual odours
- Blue dye: Disguises the appearance of waste
How Waste is Processed
- Deposit: Waste falls directly into the holding tank
- Contact: The blue chemical immediately begins working on the waste
- Breakdown: Bacteria are killed, and organic matter starts decomposing
- Neutralisation: Odours are chemically neutralised, not just masked
Chemical Safety
Modern portaloo chemicals are non-toxic and biodegradable. They’re designed to be effective while remaining safe for users and environmentally responsible for disposal.
Ventilation and Odour Control
Effective odour control relies on more than just chemicals—the ventilation system plays a crucial role:
The Stack Effect
Portaloos use a principle called the stack effect:
- Warm air rises naturally inside the unit
- Vents at the base draw in fresh air
- A tall vent pipe on the roof pulls odours upward
- Fresh air circulation prevents stagnant smells
Ventilation Design Features
- Louvred vents: Allow airflow while blocking debris
- Roof-mounted stack: Releases odours above head height
- Sealed waste tank: Prevents gases escaping into the cabin
This passive ventilation system works 24/7 without power, making it ideal for remote locations.
The Hand Washing System
Hygiene facilities are essential for any portable toilet. Here’s how the hand washing system works:
Fresh Water Supply
A separate fresh water tank (typically 40-60 litres) supplies the hand wash basin. This water is:
- Completely isolated from the waste system
- Refilled during each service visit
- Gravity-fed or pump-operated depending on the unit
Hot Water Options
For enhanced hygiene, especially in winter, we offer units with hot water:
- 110V Hot Water Units: Connect to site power for safe hot water
- 240V Mains Units: Unlimited hot water for permanent installations
Hot water significantly improves hand washing effectiveness—a key consideration under construction welfare regulations.
Soap and Drying
Standard units include:
- Hand soap dispenser (refilled weekly)
- Paper towel dispenser or hand dryer
- Mirror for user convenience
How Portaloos Are Serviced
Regular servicing is what keeps portaloos hygienic and odour-free. Here’s what happens during a professional service visit:
The Servicing Process
Step 1: Waste Removal A service technician connects a vacuum hose to the holding tank and pumps out all waste into a tanker truck. This takes just a few minutes.
Step 2: Tank Cleaning The empty tank is pressure-washed to remove any residue, ensuring it’s completely clean before refilling.
Step 3: Chemical Refill Fresh blue chemical solution is added to the tank—typically 10-15 litres depending on expected usage.
Step 4: Fresh Water Top-Up The hand wash water tank is refilled with clean water.
Step 5: Consumable Restocking
- Toilet paper replaced
- Hand soap refilled
- Paper towels restocked
Step 6: Interior Sanitisation All surfaces are cleaned and sanitised, including:
- Toilet seat and lid
- Walls and door handle
- Hand wash basin
- Floor
Where Does the Waste Go?
All waste is transported to a licensed treatment facility where it’s processed before entering the sewage system. This process is strictly regulated by the Environment Agency to ensure environmental safety.
At Sitech, we handle all waste disposal as part of our weekly servicing included with every hire.
Different Types of Portable Toilets
Not all portaloos work the same way. Here are the main types:
Chemical Portable Toilets
The standard type described above, using blue chemical solutions:
- Best for: Construction sites, short-term events
- Example: Maxim 3000
Mains-Connected Toilets
These connect to water and sewage systems for a more traditional flush:
- Best for: Long-term sites, permanent installations
- Example: 240V Mains Unit
- Advantage: Unlimited capacity, true flush operation
Event Toilets
Premium units designed for guest comfort:
- Best for: Weddings, festivals, corporate events
- Example: Shorelink Event Toilet
- Features: Better aesthetics, air fresheners, mirrors
Accessible Toilets
Larger units designed for wheelchair users:
- Best for: Public events, inclusive sites
- Example: Disabled Access Unit
- Features: Ramp access, grab rails, extra space
For help choosing the right type, see our guide on chemical vs mains connected toilets.
Frequently Asked Questions
How does a portaloo flush work?
Most portaloos don’t have a traditional flush. Instead, they use a chemical holding tank system. When you close the toilet lid or use a foot pump (on some models), a small amount of blue chemical solution is released to cover waste and control odours. The waste drops directly into the holding tank below, where the chemicals break it down and neutralise smells.
What is the blue liquid in portable toilets?
The blue liquid is a specially formulated biocide solution containing fragrance, dye, and bacteria-killing agents. It serves three purposes: killing odour-causing bacteria, breaking down waste and toilet paper, and masking unpleasant smells with fragrance. The blue dye also helps hide the appearance of waste in the tank.
How often do portaloos need to be emptied?
Standard portaloos should be serviced and emptied at least once per week for normal use. High-traffic units at events may need daily servicing. The holding tank typically holds 200-250 litres, which is sufficient for approximately 100 uses before requiring emptying.
Do portaloos smell bad?
Well-maintained portaloos should not smell bad. Modern units use powerful chemical solutions, effective ventilation systems, and regular servicing to control odours. Problems only arise when units are overused, not serviced regularly, or damaged. Weekly professional servicing is key to keeping units fresh.
How do portaloos work without water?
Portaloos use a chemical waste system instead of water-based flushing. Waste falls directly into a holding tank containing biocide chemicals that neutralise odours and break down matter. A separate fresh water tank supplies the hand wash basin. This self-contained design allows portaloos to work anywhere without mains water connection.
Where does portaloo waste go?
When a portaloo is serviced, the waste is pumped into a tanker truck using a vacuum system. The waste is then transported to a licensed treatment facility where it undergoes processing before being safely disposed of through the sewage system. All waste disposal must comply with Environment Agency regulations.
Can you use a portaloo in winter?
Yes, portaloos work year-round. However, in very cold weather, units with hot water facilities provide much better hand washing. Our 110V hot water units are specifically designed for winter construction sites.
How many people can use a portaloo before it needs servicing?
A standard unit can handle approximately 100 uses before the holding tank is full. For a typical construction site with 7 workers using facilities twice per shift, this equates to about one week—which is why weekly servicing is the standard.
Conclusion
Portaloos work through a clever combination of chemical waste treatment, passive ventilation, and regular professional servicing. The blue chemical solution neutralises odours and breaks down waste, while the ventilation system keeps air fresh. Weekly servicing ensures tanks are emptied, consumables restocked, and everything thoroughly sanitised.
Understanding how these systems work can help you make better decisions about your site welfare needs. Whether you need a standard construction unit or a premium event toilet, the fundamentals remain the same—good chemicals, good ventilation, and good servicing.
Need portable toilets for your project? Sitech Loos London provides fully serviced units with weekly maintenance included as standard. Get an instant quote or call us on 01279 432 944 to discuss your requirements.
Related Articles
- Chemical vs Mains Connected Portable Toilets
- Construction Welfare Regulations 2026
- Construction Site Toilet Hygiene Standards
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