Owhiro Bay water quality

Update 19 February

We are currently undertaking water quality sampling in Owhiro Bay; daily at the stream mouth, and weekly at the Baywatch site (on the other side of the bay).

Below are the latest results.

Owhiro Bay sampling2

Update 4 February

We have followed our protocols recommending the reopening of the beach. A source of the spike in contamination was identified and the sampling at the long term beach monitoring site had returned to normal. We acknowledge that our communication could have been better as removing the warning signs implies that the Owhiro Stream, that crosses the beach, is safe for swimming in. Owhiro Stream, like many urban waterways, has a long history of contamination and is regularly unsafe for swimming in. Improving the quality of Owhiro Stream will require a coordinated and long term programme of works.

We have identified water quality as one of our key focus areas for our client councils to consider in the preparation of their upcoming Long Term Plans. In the short term Wellington Water will implement a permanent sign at the mouth of the Owhiro Stream warning people of the potential water quality issues.

Update 30 January

The beach has returned to safe levels and our investigations of the likely sources in the catchment has just been completed with 3 cross-connections found. We will be removing the warning signs today.

Thanks to the wider community for your patience and understanding as we worked through resolving these cross-connections.

Update 29 January

Our operations team have been hard at work resolving cross-connections in the network. As a result of this work, we are seeing an improvement in the water quality in Owhiro Bay.

We are continuing with our routine sampling, and are looking at when it is appropriate to take down the warning signs. For now, they are still in place. We will confirm when signage comes down.

What's happening?

The water quality in Owhiro Bay is being affected by a cross-connection. A cross-connection is where a wastewater pipe is connected into a stormwater pipe. Most cross-connections are from private pipes into public (council) pipes, and this is the case here. Wastewater from private properties is entering the stormwater system, which leads to Owhiro Stream, which leads to the Bay. We are working with the property owners concerned, who were not aware of the issue, to resolve it as quickly as possible.

Contamination from cross-connections can be difficult to locate. Wastewater flows are not constant - they depend on usage. To find the source we have to take samples, send them to the laboratory for testing, and then get the results. This takes a couple of days. We have to work our way methodically upstream to narrow down the area where the contamination is coming from.

We're working with property owners to resolve cross-connections we've identified. We expect to have these sorted by the end of the week. We're also continuing our investigation and testing; it can be a mistake to think the first fault you come across will fix the problem.

If you have concerns about what you think might be a cross-connection at your place, please let us know and we'll come and take a look. Our main concern is to eliminate as many of these as we can.

Warning signs that recommend against swimming and fishing in Owhiro Bay remain in place, and will stay there until we receive three consecutive days of clear results. We will update via social media and the website when this changes.

If you have been swimming in the area and feel sick, please visit your doctor.