The lake belongs to everyone. So does caring for it.
What we do at home, in the fields, at work and as visitors ends up in the water. Small changes by each of us are what will save it.
Orange alert for cyanobacteria
Blooms have appeared every year since 2009. Some 327,000 people live in the basin, across 15 municipalities.
Source: AMSCLAE in Prensa Libre
What pollutes the lake?
According to AMSCLAE, the main sources are untreated wastewater, poorly managed garbage and farm fertilizers, which the rain washes down from across the basin. They come from homes, fields, streets and businesses in all fifteen municipalities.
Drains, cesspits and latrines that reach the ground or the lake untreated.
Whatever is thrown into the ravine, the river or the street, the rain carries down to the lake.
The nutrients they carry feed the cyanobacteria.
What we believe and what actually happens
We all contribute. Water from every home, every field and every business in the basin reaches the lake, every day of the year.
A cesspit cleans nothing: it leaks sewage into the ground and pollutes the groundwater we later drink. The solution is a biodigester or a connection to a treatment plant.
Soap and detergent carry nutrients that feed the cyanobacteria. Washing away from the shore, at washhouses with proper drainage, protects everyone's water.
With the first rain it washes down rivers and streams. Sorting your garbage and handing it to the municipal collection service is caring for the lake.
Responsible practices
- A biodigester instead of a cesspit
- Connect to treated sewage where available
- Wash clothes away from the shore
- Separate organic waste, recyclables and trash
- Compost kitchen scraps
- Zero single-use plastics, as required by Acuerdo Gubernativo 189-2019
- Wastewater treatment at your hotel or restaurant
- Refill water instead of bottles
- Biodegradable cleaning products
- Buy from local producers
- Bring a reusable bottle and bag
- Don't use soap or sunscreen in the lake
- Take your trash with you from trails and lookouts
- Choose businesses with good practices
- Respect the tul (lake reeds) and the shoreline
San Pedro La Laguna said no to plastic in 2016
It banned the sale of single-use plastics. Its mayor reported that 80% of residents stopped using them, and other municipalities followed its lead.
Read more →Initiatives we support
Community washhouses with drainage to treatment.
Support for municipalities to build them and keep them running.
Information and contacts to install them in homes and businesses.
A badge in the directory for businesses with verified good practices.
Sources: Prensa Libre and AMSCLAE (May 2026) · Acuerdo Gubernativo 189-2019 · World Economic Forum