As a swimming pool owner in the Tasman District Council area, it's important to understand the regulations regarding the discharge of pool water to our environment and the requirements outlined in our wastewater bylaw. Here's what you need to know:
Swimming pool water contains contaminants that can be harmful to our environment
You are only allowed to discharge clean water without contaminants into our freshwater environment. Discharges into our stormwater system, such as sumps and drains, flow directly into our natural aquatic environment – our rivers, streams and estuaries. There are rules in our Nelson Tasman Resource Management Plan which restrict these discharges.
Filter backwash water needs to go into the wastewater system
As backwash water contains contaminants, it must be discharged into the wastewater system. However, this water must meet the conditions in our wastewater bylaw, have a pH of between 6 & 9 and contain less than three parts per million (ppm) of chlorine[EM1] (equivalent to three milligrams per litre or three grams per cubic metre).
Emptying your pool or spa
Firstly, does your pool really need to be emptied?
Pools rarely need to be completely emptied: at the most every 5-7 years
Only empty your pool if it is needed for excessive chemical imbalances, high levels of total dissolved solids or structural repair.
Generally, water quality issues can be resolved with chemical treatments. Talk to your pool specialist for advise.
Emptying your pool is a risk to the integrity of the pool and strains local water resources.
If you decide you need to empty your pool or spa, then there are a few things to consider
Pools using chlorine, bromine or other chemicals
Stop treating your pool with chemicals a week before emptying it. Chlorine or bromine will eventually evaporate. However, if you are using other chemicals, these may persist in the water.
We encourage you to use the water to irrigate your lawn or let it soak into the ground where the water does not run off into a stream, stormwater drain, or neighbouring properties. If this is not possible, discharge to the wastewater system in accordance with the Wastewater Bylaw rules (see below).
Saltwater pools
If you have a saltwater pool, then it is unsuitable to discharge to any stormwater system or freshwater environment, and discharging it to land will degrade your soil quality over time. Therefore, all saltwater pools will need to be discharged into the wastewater system, in accordance with the Wastewater Bylaw (see below).
Discharging to the wastewater system
You will need to contact the council before discharging to the wastewater system to ensure that there is enough capacity.
When discharging any pool or spa water to our wastewater system, you will need to comply with our wastewater bylaw and:
You may only discharge between 8pm and 7am, at the recommended flow rate of 0.4 litres per second (l/sec). This is achieved by having a flow limiting device fitted to the outlet of the pool or spa.
You may not discharge during a rain event that exceeds 20mm in a 24 hr period, or within the three days following that event. Information on this can be found on our interactive rainfall report.
Water flowing out of your pool via the overflow or skimmer during rain events cannot be directly connected to the council’s wastewater network
During rain events, outdoor pools are likely to collect rainwater directly, or through surface run-off. The wastewater system is designed to convey and treat sewerage and adding extra water during rain events can cause wastewater systems to get overwhelmed and overflow - causing serious health and environmental threats. Therefore, it is important to ensure that the overflow from the pool is not connected into the wastewater system.
This can be achieved by either:
Not having an overflow connection and let the pool fill up and spill over.
Having an overflow that is connected to a soakage pit.
Having a pool cover that covers the entire pool and sheds water away from the pool.
Report any conspicuous discharges
If you observe any pollution or unauthorised discharge into waterways, please report it to us immediately by calling 03 543 8400.
Additional information
The relevant information regarding Swimming Pool and Spa Pool discharge can be found in Part B, Section 5 of the Wastewater Bylaw. (pdf 635 KB)
5. Swimming Pool or Spa Pool Discharge
No person shall discharge water from a swimming pool or spa pool into the wastewater system unless the discharge complies with all applicable requirements in this Part B Clause 5, in which case the discharge will be a permitted discharge acceptable to the Council.
The discharge of backwash water from a domestic swimming pool or spa pool is permitted only if: (a) the residual chlorine level of the backwash water is less than 3ppm; and (b) the quantity of the discharge is an amount associated with a standard backwash of filters.
If the reason for the discharge of backwash water from a domestic swimming pool or spa pool into the wastewater system is due to a chemical imbalance (including pH9) in the backwash water, the person carrying out the discharge must consult the Council before the discharge occurs.
All discharges of water from a domestic swimming pool or spa pool, other than backwash water, shall be made after 8.00pm and before 7.00am. Discharges outside these times shall only be with the approval of Council. Council reserves the right to limit (including by resolution) the rate and timing of the discharge and to impose any other conditions it considers appropriate. Discharges are not allowed during, or in the three (3) days following, a rain event exceeding 20mm in a 24-hour period.
A flow limiting device must be fitted to any domestic swimming pool or spa pool that is capable of discharging into the wastewater system and must be in use at the time of discharge to ensure that the discharge does not exceed the maximum instantaneous flow requirement of 1.0 l/sec. The Council reserves the right to further limit the rate and timing of any discharge. The discharge of stormwater and rainwater captured by a swimming pool to the wastewater system is not permitted.
The relevant section is 36.2.2.8 Discharge of Water:
The discharge of water into water is a permitted activity that may be undertaken without a resource consent, if it complies with the following conditions:
The discharge does not cause erosion of the bed of any river or stream.
The discharge does not contain more than 0.5 grams per cubic metre of free or residual chlorine.
Except as provided for in condition (b), the discharge does not contain contaminants other than heat.
When the natural temperature of the water is less than 20 degrees Celsius, the water temperature is not increased by more than 3 degrees Celsius and in any event does not exceed 20 degrees Celsius. When the natural temperature of the water is 20 degrees Celsius or greater, there is no increase in water temperature.
The rate of discharge does not exceed 5 litres per second.
Contact us
If you have any further questions, please call us on 03 543 8400 and ask to be put in contact with the stormwater team.
Thank you for your cooperation in protecting our environment and complying with the regulations governing the discharge of swimming pool water. Together, we can ensure the health and sustainability of our water resources for future generations.
