Fluoride has also been found across 930 areas in 13 districts.
The groundwater of 24 districts of Assam has been contaminated by arsenic, while that in 13 districts affected by fluoride, the state assembly was informed on Thursday.
Assam has 33 districts.
Replying to a query by AGP MLA Ramendra Narayan Kalita during Question Hour, Public Health Engineering Minister Rihon Daimary said groundwater in 6,881 areas of 24 districts is contaminated by arsenic.
Fluoride has also been found across 930 areas in 13 districts, he added.
The government has established 227 and 40 schemes for arsenic and fluoride free water respectively at various locations, Daimary said.
"The Centre has also approved 122 schemes for arsenic-free water in the state. But we have not been able to implement these as we have not got land for them. I request all the MLAs to help us in acquiring land for this purpose," he added.