How To Fix Water Pollution in Cities: Skylines

The best way to fix water pollution is by making sure your sewage plants and water pumps are placed far away from each other.

But whether you want to plan your city before building it, or if you currently have a water pollution problem, these various methods can help you minimize pollution risk.

Plan your city ahead of time for strategic placement of sewage outputs (Most Efficient)
Use the edges of the map to limit water pollution (Easiest Method)
Check the flow of the water to avoid further pollution
If water is limited, dump sewage on land
Let nature remove pollution on its own
Green Cities DLC – Use eco sewage treatment plants and floating garbage collectors

Method #1: Planning your City Ahead of Time (Best Method)

The best way to keep water pollution away from your city is to plan before you build. Decide where you want your city and your clean water, then plan where the sewage will be pumped to. Keep the water pumps and sewage plants separate when at all possible.

A look at how separation of sewage and water pumps can keep your citizens healthy (Arrow shows the flow of the water)

As shown in the image above, the sewage and water pumps are separated from each other.

This may not reduce pollution from the sewage itself, but it keeps the fresh water supply to your city completely free of pollution.

Method #2: Watch out for Water Currents

When placing buildings that have to do with water, the flow of the water is shown with arrows.

It’s important to make sure that the flow of the water will not carry polluted water into a clean water pump. However, these currents can be beneficial if used correctly, as shown below.

An example of water flow carrying polluted water into a clean water pumps

Note: Even if a sewage plant is downstream of a water pump, the force of the water pump can reverse the natural flow of the water. Be careful and make sure they are far enough away from each other.

When sewage pumps are placed at the edge of the map and the water is flowing in the right direction, the sewage is instantly swept out of the area, leaving you worry-free about the spread of water pollution.

If your map has an outflow off the map like shown in the picture below, this method is the easiest way to keep water pollution to a minimum.

A sewage pump placed at the edge of the map

Method #3: Dump Sewage on Land

If your map’s water supply is naturally low, dumping sewage on land can be an option for waste disposal.

This will keep your water free of pollution, but keep in mind that ground pollution will still occur. Try placing land-based sewage outputs in already polluted areas. (ex. By a landfill, industry area, etc.)

An example land-based sewage disposal set-up

Keep in mind that sewage is like water – it will flow downhill and may create its own pool of sewage. To combat this, use landscaping tools to create a hole in the ground or slope the ground to flow the sewage off the map.

Note: Keep an eye on land-based sewage areas; if your hole is not deep enough or has filled up, the sewage can overflow and cause even more problems.

Method #4: Let Nature Takes its Course

If the other methods have not worked for you, then another solution is to relocate the sewage plants to another location and let nature remove the pollution on its own.

Over time, ground/water pollution caused by sewage will fix itself and the pollution will be removed.

Note: this process takes quite some time, so to use the method properly you should only use it in dire circumstances. When you relocate, try to use the previous methods in this article when planning where to put your sewage plants.

Method #5: Use Specialized Buildings from the Green Cities DLC

In order to use this method, you will have to have purchased the Green Cities DLC to access the special buildings required. The buildings that are included in this DLC for sewage management are listed below.

The Eco Water Outlet
The Eco Water Treatment Plant
The Floating Garbage Collector

This table will lay-out the differences between the DLC structures and their vanilla counterparts.

DLC Building	Difference vs Vanilla Buildings
Eco Water Outlet	Reduces pollution output Requires more energy More Expensive to build Drains half the amount of sewage
Eco Water Treatment Plant	Pollution output reduced by 94% (as opposed to 85%) More expensive to build Requires 2.5x the amount of energy

Floating Garbage Collectors can be placed on water to clean it. If there is already a polluted area of water, place these structures down to slowly remove the pollution.

So What’s The Best Fix?

The absolute single best way to keep water pollution out of your water supply is to plan your city to keep sewage plants and water pumps away from each other. Using this method, your water supply should remain uncontaminated throughout your entire game.

If you already have a pollution problem, your best option then would be to move the sewage plants to more strategic locations as discussed above, and use Floating Garbage collectors to aid the natural pollution clean-up.