Drain Plumbing 101: Complete Guide to Common Issues and Solutions

1. Slow Draining

Slow drains are often the first sign of a developing blockage. Water takes longer than usual to drain away, and you might notice pooling in sinks or showers. This is particularly common in New Zealand due to our soft water and the buildup of minerals over time.

Common Causes:

• •
  Hair and soap buildup: The most common cause in bathroom drains. Hair combines with soap scum to form thick clogs that gradually restrict water flow.
• •
  Grease accumulation: Kitchen drains suffer from grease, oil, and food particles that solidify in pipes, especially during colder months.
• •
  Foreign objects: Items like cotton buds, dental floss, and food scraps that shouldn't be in drains.
• •
  Tree root intrusion: Very common in older NZ properties where tree roots penetrate pipes seeking moisture, particularly willows and poplars.
• •
  Pipe scale buildup: Mineral deposits from hard water areas gradually reduce pipe diameter.

2. Complete Blockages

A complete blockage means no water can pass through the drain at all. This is a plumbing emergency that requires immediate attention to prevent overflow and water damage.

Common Causes:

• •
  Ignored slow drains: Most complete blockages start as slow drains that worsen over time.
• •
  Collapsed pipes: Common in older NZ homes with clay or concrete pipes that have deteriorated.
• •
  Foreign object obstruction: Large items flushed down toilets or washed down drains.
• •
  Severe root infiltration: Tree roots can completely fill pipes, creating solid blockages.

3. Recurring Blockages

If you're experiencing blockages in the same drain repeatedly, there's likely an underlying structural issue that needs professional assessment.

Possible Causes:

• • Incorrect pipe gradient causing poor drainage
• • Bellied or sagging pipes where debris accumulates
• • Damaged or deteriorating pipes with rough interior surfaces
• • Partial pipe collapse creating permanent restrictions

4. Bad Odors

Foul smells coming from drains indicate trapped debris, dry traps, or more serious issues with your sewerage connection.

Common Causes:

• • Dry P-traps in rarely used drains
• • Decomposing organic matter in pipes
• • Blocked vent pipes preventing proper drainage
• • Sewerage backup from main line issues

5. Gurgling Sounds

Unusual gurgling or bubbling sounds from drains often indicate air trapped in pipes due to blockages or venting problems.

What It Means:

• • Partial blockages creating air pockets
• • Blocked vent stack preventing proper air flow
• • Main sewer line problems affecting multiple fixtures
• • Negative pressure in drainage system

High-Pressure Water Jetting

Also known as hydro-jetting, this is the most effective method for clearing stubborn blockages and cleaning pipe interiors. A specialized machine propels water at extremely high pressure (up to 5000 PSI) through pipes, cutting through tree roots, grease, and scale buildup.

Best For:

• • Severe blockages and tree root removal
• • Grease buildup in kitchen drains
• • Preventive maintenance of main lines
• • Removing scale and mineral deposits

Electric Drain Cleaning (Drain Snake)

Professional-grade electric drain snakes (also called drain augers) use a rotating cable with cutting attachments to break through blockages. These are more powerful than DIY versions and can reach much further into your drainage system.

Best For:

• • Solid obstructions like tree roots
• • Hair and soap buildup
• • Reaching distant blockages
• • Breaking up hard materials

CCTV Drain Inspection

Before attempting repairs, professional plumbers often use CCTV cameras to inspect the inside of your pipes. This helps identify the exact location and nature of the problem, preventing unnecessary excavation and ensuring the right solution is applied.

What It Reveals:

• • Exact location of blockages
• • Pipe condition and material type
• • Tree root intrusion points
• • Cracks, breaks, or collapsed sections
• • Incorrect installations or connections

Chemical Treatments

Professional plumbers use commercial-grade drain cleaners that are much stronger than retail products. However, these are typically used as a last resort or for specific situations due to potential pipe damage and environmental concerns.

When Used:

• • Dissolving organic matter
• • Treating grease buildup
• • Killing tree roots in combination with other methods
• • Preventive maintenance treatments

Manual Drain Snaking

For smaller blockages close to the drain opening, manual snaking remains an effective and economical solution. Professional manual snakes are longer and more durable than DIY versions.

Best For:

• • Simple hair and soap blockages
• • Accessible drain sections
• • Minor obstructions near drain openings
• • Preventive cleaning of P-traps

1. Boiling Water Method

The simplest solution for grease and soap buildup. Particularly effective for kitchen drains.

How to Do It:

1. 1. Boil a full kettle of water
2. 2. Slowly pour it directly down the drain in 2-3 stages
3. 3. Wait a few seconds between pours
4. 4. Repeat if necessary

2. Baking Soda and Vinegar

A natural, environmentally friendly solution that's safer for pipes than chemical cleaners.

Step-by-Step Process:

1. 1. Pour one cup of baking soda down the drain
2. 2. Follow with one cup of white vinegar
3. 3. Cover the drain immediately to contain the reaction
4. 4. Wait 30 minutes (or overnight for stubborn clogs)
5. 5. Flush with hot water

Best for: Mild to moderate organic buildup, soap scum, and minor grease accumulation.

3. Plunger Technique

Often overlooked, proper plunging technique can clear many blockages without chemicals or tools.

Proper Plunging Method:

1. 1. Ensure there's enough water to cover the plunger cup
2. 2. Block overflow drains with a wet cloth
3. 3. Create a tight seal over the drain
4. 4. Pump vigorously 15-20 times
5. 5. Break the seal quickly to create suction
6. 6. Repeat several times if needed

4. Manual Drain Snake

Available from hardware stores for $15-50, manual drain snakes can reach blockages up to 6-8 meters into your drainage system.

How to Use:

1. 1. Insert the snake into the drain opening
2. 2. Push slowly while rotating the handle
3. 3. When you hit resistance, rotate vigorously
4. 4. Push and pull to break up the blockage
5. 5. Slowly withdraw the snake
6. 6. Flush with hot water

5. P-Trap Cleaning

The P-trap (the curved pipe under your sink) is designed to trap debris and can be manually cleaned.

Cleaning Process:

1. 1. Place a bucket under the P-trap
2. 2. Unscrew the slip nuts holding the P-trap
3. 3. Remove and empty the P-trap
4. 4. Clean thoroughly with a brush
5. 5. Check for damage or wear
6. 6. Reassemble, ensuring tight connections
7. 7. Test for leaks

Daily and Weekly Habits

• ✓
  Use drain strainers: Install mesh strainers in all sinks, showers, and tubs. Empty them daily to prevent hair and debris from entering pipes. These cost $5-15 each but save thousands in potential repairs.
• ✓
  Flush with hot water: After each use of kitchen sinks, run hot water for 30 seconds to help dissolve and flush away grease before it solidifies in pipes.
• ✓
  Wipe plates before washing: Scrape all food scraps into the rubbish bin before washing dishes. Even small particles accumulate over time.
• ✓
  Brush hair before showering: Removing loose hair before showering significantly reduces the amount going down drains.

Monthly Maintenance Tasks

• ✓
  Baking soda treatment: Pour half a cup of baking soda followed by hot water down each drain monthly. This prevents buildup and keeps drains smelling fresh.
• ✓
  Check P-traps: Ensure P-traps under sinks haven't dried out, especially in guest bathrooms or laundry areas. Run water in rarely-used drains to maintain the water seal.
• ✓
  Inspect outdoor drains: Check gully traps, stormwater drains, and grates for leaves, dirt, and debris. Clean as needed to prevent blockages during heavy rain.
• ✓
  Test drain flow: Note how quickly water drains from each fixture. Slower drainage is an early warning sign of developing blockages.

Annual Professional Maintenance

• ✓
  Professional drain cleaning: Schedule annual drain cleaning, particularly for main lines and frequently used drains. This costs $250-400 but prevents emergency repairs costing $500-1,000 or more.
• ✓
  CCTV inspection: For properties with mature trees nearby, consider a CCTV inspection every 2-3 years to catch root intrusion early. This costs $200-400 but can prevent $2,000-5,000 in pipe replacement costs.
• ✓
  Hot water jetting: For properties prone to grease buildup or with a history of blockages, annual high-pressure cleaning maintains optimal flow and pipe condition.

What Never to Put Down Drains

How often should I have my drains professionally cleaned?

For most homes, annual cleaning of main drains is sufficient. However, if you have mature trees nearby, experience frequent issues, or run a commercial kitchen, consider cleaning every 6 months. Properties with older drainage systems may also benefit from more frequent maintenance.

Can tree roots really damage my pipes?

Absolutely. Tree roots are one of the most common and serious drainage problems in New Zealand. They can penetrate even small cracks in pipes, then expand to completely block or even break pipes. Willows, poplars, and other water-seeking trees are particularly aggressive. If you have mature trees within 10 meters of your drainage lines, consider regular CCTV inspections.

Are chemical drain cleaners safe to use?

While they can work for minor clogs, chemical drain cleaners have significant drawbacks. They can damage pipes (especially older systems), harm the environment, and are dangerous to handle. They're also ineffective against major blockages like tree roots. For best results and pipe longevity, use mechanical methods or call a professional.

What's the difference between storm water and wastewater drains?

Stormwater drains carry rainwater from roofs, gutters, and outdoor surfaces to the street or natural watercourses. Wastewater drains handle water from sinks, showers, toilets, and appliances, going to the sewerage system for treatment. In NZ, it's illegal to connect these systems. Stormwater must not enter the sewerage system as it can cause overflows during heavy rain.

How do I know if I need pipe replacement or just cleaning?

This requires professional assessment, usually with a CCTV camera inspection. Signs you might need replacement include: frequent recurring blockages despite cleaning, visible cracks or damage, collapsed pipe sections, severe root infiltration throughout the pipe, or pipes made from outdated materials like asbestos cement. Modern pipe replacement techniques like pipe relining can often fix issues without extensive excavation.

Will my insurance cover drain repairs?

This depends on your policy and the cause of the problem. Most policies cover sudden or accidental damage (like a burst pipe) but not gradual deterioration or lack of maintenance. Tree root damage coverage varies by insurer. Always check your policy details and maintain records of regular maintenance, as some insurers require evidence of proper upkeep.

Can I install a garbage disposal unit in New Zealand?

Yes, but they're less common here than in other countries. You'll need council consent, and your drainage system must be suitable. Some areas prohibit them due to concerns about sewerage system capacity. They can also contribute to blockages if not used properly. Consult your council and a licensed plumber before installation. Many NZ plumbers recommend composting or regular rubbish disposal instead.

What should I do if my drain is blocked after hours?

First, turn off water supply to the affected fixture to prevent overflow. If it's a single drain, you can often wait until morning for non-emergency service, saving on after-hours fees. However, call an emergency plumber immediately if: multiple drains are affected, sewage is backing up, water is overflowing and causing damage, or you smell gas or sewerage odors throughout the house.