Your Lagoons

Who doesn’t love a good lagoon? Who doesn’t love a good west coast lagoon? The mere thought of the word conjures up memories of many a pleasurable day trip: heading off through the ranges, along nauseatingly winding roads, pulling up in the dusty car park and scampering off across the black sand engaging your most strategically advanced footwork so as to avoid burning the soles of your feet off, only to be greeted with waves so overwhelmingly gigantic you’d have to breathe into a brown paper bag to regain your composure.

But it was ok, there was always The Lagoon – Trusty Option B. Every beach came equipped with one. No waves, no dramas, just floating on your back à la starfish, with the occasional break to get shaken on by a wet dog, munch on a sandy bag of salt ‘n’ vinegar chips or enthusiastically splash your mother if she so much as thought of taking a swim. Those were good memories. Memories I am sure we all want to continue having, and want our children, mothers and dogs to have for many years to come….

Love Our Lagoons

Water quality in our beloved Waitakere lagoons (Karekare, Piha, North Piha and Te Henga) has unfortunately been of concern for locals, Tangata Whenua and Auckland Council for several decades. Although the lagoons seem like a relatively safe option compared to the often intimidating west coast surf, they frequently pose a health risk due to contamination. This contamination has been linked to a number of possible sources, but our data suggests that the main culprits are malfunctioning septic tanks and long drops from houses in the immediate area. This causes chemical residues (from washing and cleaning) and untreated human waste to enter the lagoon which in turn cause problems not only affecting our enjoyment of the lagoons, but also the health of those that call the lagoons home – including some of our most unique flora and fauna.

The purpose of the Love Our Lagoons project is to improve water quality by reducing contaminant input from these sources so everyone can once again enjoy splashing their mums and starfishing the day away in a healthy, clean environment.

But I love the Lagoons! How can show it?

Our philosophy is that making the lagoons cleaner can only be achieved if we work together. So our main approach is to work directly with the local community to raise awareness and get residents involved on a very practical level to reduce their contribution to the problem. Last summer we set up community engagement events at the beach, did some old-fashioned door knocking and completed a number of technical assessments on properties in our priority areas. We had a fantastic response and raised a lot of awareness, so we’re off to a good start!

The main thing you can do is share what you’ve learned with others and encourage them to take part too. If you live on the coast, have friends that live on the coast, or find yourself there for a holiday – let others know what we’re trying to achieve and when it comes time to use the powder room, show the septic tank some love too!

It’ll take a bit of time, but it really is all about thinking about what you’re doing, when you’re doing it,  keeping things in working order and telling your mates how fun it all is so they can do it too!

In the meantime we suggested to be careful and vigilant about swimming in the lagoons, especially with young children and particularly after rain.

I live on the west coast and love my lagoon like crazy! How can I help?

The most important thing you can do is be active in avoiding contamination of the lagoon and the most beneficial way you can do this is by keeping your long drop or septic system working efficiently.

Now we get it, septic tanks can be a bit enigmatic! You never really know what could be going on down there and for the most part it is easy to assume they’re doing their thing correctly. But from time to time they just need a little check up which is where we can help you know where to start.

To help you understand the mysteries of the septic system, we’ve compiled some information to keep you and your septic tank on top of your game. Happy Lagoon Loving!

How do septic tanks work?

A septic tank works by separating wastewater into three layers:

scum (which floats on the surface)
liquid (middle layer)
solids/sludge (which sink to the bottom of the tank)

The liquid layer is treated in the tank, reducing bacteria and nutrients. The liquid is then distributed into the disposal field where it can soak into the ground.

Sludge and excess scum need to be pumped out of your tank every three years. Because a septic tank system relies on soakage, the soil type on your property is very important. Some soils such as clay, do not allow the wastewater to drain away rapidly enough so a portion of what went down the drain can in turn end up washed into the nearest waterway, in this case it is our lagoons.

What you can do to prevent septic tank contamination of the lagoons [maybe download a Love your lagoons handy PDF to print out and hang in the dunny]




Know your system

Know where your septic tank and drainage field is. Do not drive on it.

Divert stormwater away from drainage field.

Check regularly & watch for soggy patches or odours.

Forget it and the system is likely to clog up, pollute the environment , put you and your neighbours health at risk and be expensive to repair.

Maintain your system

Pump out your septic tank every 3 years as a rule of thumb – when it gets to be 50% full of sludge and scum.

Fit an outlet filter to present solids entering disposal field

Check filters and fix or seal lids

Flush field lines


Use less water

Take shorter showers

Flush toilet less often

Install water efficient devices

Recycle shower & bath water to irrigate plants

Reduces the amount of wastewater being created and needing treatment.

Stagger water use

Do only one load of laundry per day

Empty baths slowly

Spread your family’s showers morning and night

Large deluges of water will stir up solids and push them out into the drainage field, blocking the lines

Watch what you put into your septic tank

Don’t flush: disinfectants, chemical cleaners, chlorine bleach, hair dye, fats and oils, medicines, sanitary products

Consider adding beneficial bacteria to your septic tank.

Use phosphate & ammonia free laundry and dish washing detergents

Keep all possible solids except toilet waste out

Don’t use a waste disposal in kitchen sink

Chemicals kill the beneficial organisms that help break down waste in your septic tank.

High alkalinity & sodium salt levels destroy soil structure and reduce absorption of water into the ground.

Solids make the septic tank fill up faster, requiring more frequent pump-out.

We worked with local residents, Auckland Council, sewerage contractors and a number of other groups to develop areas in which to focus our efforts. The following maps display our key priority areas (in yellow) – areas most likely to be at risk of contributing contamination into the lagoons. Yet if the whole community takes steps to improve their behaviours, the results can only be great.

You can also follow the guidelines above to ensure you’re doing your best and also don’t be afraid to tell the world how much you love your lagoon! The more people that get on board the better!

For further information on any aspect of this project get in touch with project manager, Daniel Ducker on 021 242 338 or email

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